cold_facts_vol31_no_2_2015.pdf

Volume 31 Number 2VVoVoVoVoVoVoVoolllulululululumememememememe 33333333111111 NNNNNNNNNumumumumumumumbbebebebebebeberrrrr r 222222Volume 31 Number 2

Developments We Most Wish to See ................. 25Featuring Women in Cryogenics and SC ........... 38Calendar ............................................................. 49

Helium Dewar Simulation with No Liquid Cryogens ..8Glen McIntosh’s Kryo Kwiz ................................. 13Lab-Based ADR Cryostats ................................. 20

Technology Focus: Cryocoolers and Cryostats | 16

Join Our Growing Family of CSA Corporate Sustaining Members

Get connected to the cryogenic community worldwide. Let your voice be heard and your contributions known.

Abbess Instruments and Systems, Inc.

Ability Engineering Technology, Inc.

Acme Cryogenics, Inc.

Advanced Piping Products

Advanced Research Systems, Inc.

Aerospace Fabrication & Materials

Air Liquide advanced Technologies

American Magnetics, Inc.

Amuneal Manufacturing Corp.

Argonne National Laboratory

Barber-Nichols, Inc.

Bauer Compressors

BellowsTech, LLC

Brooks Automation, Inc. Vacuum Products Division

Bürkert Fluid Control Systems

CAD Cut, Inc.

Cameron Valves and Measurement

CCH Equipment Company

Chart Inc.

Circor Cryogenics–CPC Cryolab

Circuit Insights LLC

Clark Industries, Inc.

Coax Co., Ltd.

Composite Technology Development, Inc.

Cool Pair Plus

Cryo Industries of America

Cryo Technologies

Cryoco LLC

Cryocomp

Cryoconnect, Div. of Tekdata Interconnections Ltd.

Cryofab, Inc.

Cryogas Tech Sdn. Bhd.

Cryogenic Control Systems, Inc.

Cryogenic Industries, Inc.

Cryogenic Institute of New England

Cryogenic Limited

Cryogenic Machinery Corporation

Cryoguard Corporation

Cryomagnetics, Inc.

Cryomech, Inc.

Cryonova, LLC

Cryotherm GmbH & Co. KG

CryoVac GmbH

CryoWorks, Inc.

CryoZone, a brand of DH Industries

CSIC Pride (Nanjing) Cryogenic Technology Co., Ltd.

Demaco Holland BV

DH Industries BV

DH Industries India Pvt. Ltd.

DH Industries USA, Inc.

DMP CryoSystems, Inc.

Eden Cryogenics, LLC

Essex Industries

Fermi National Accelerator Laboratory

Fin Tube Products, Inc.

Flexure Engineering

Gardner Cryogenics

HPD

Hypres, Inc.

Independence Cryogenic Engineering, LLC

Indium Wire Extrusion

INOXCVA

Instant Systems, Inc.

International Cryogenics, Inc.

ISOFLEX USA

Janis Research Co., Inc.

Kadel Engineering Corp.

Karlsruhe Institute of Technology

Kelvin International Corporation

Kelvin Technology, Inc.

KEYCOM Corporation

L&S Cryogenics

L-3 Communications Cincinnati Electronics

Lake Shore Cryotronics, Inc.

Linde Cryogenics, Division of Linde Process Plants, Inc.

Lydall Performance Materials

Magnatrol Valve Corporation

Master Bond

Mesuron, LLC

MEWASA Ag, Inc.

Meyer Tool & Mfg., Inc.

Midwest Cryogenics

MMR Technologies, Inc.

Molecular Products, Inc.

NASA Kennedy Cryogenics Test Laboratory

National High Magnetic Field Laboratory

National Superconducting Cyclotron Laboratory—MSU

Nexans Deutschland GmbH

Niowave, Inc.

Oak Ridge National Laboratory

Oxford Instruments Omicron NanoScience

PHPK Technologies

Precision Measurements and Instruments Corp.

Prentex Alloy Fabricators, Inc.

Quantum Design, Inc.

Ratermann Cryogenics

Ratermann Manufacturing, Inc.

Redstone Aerospace

RegO Products

RICOR USA

RUAG Space GmbH

Scientific Instruments, Inc.

SGD Inc.

Shell-N-Tube Pvt. Ltd.

shirokuma GmbH

Sierra Lobo, Inc.

Spaulding Composites Inc.

SPS Cryogenics BV

STAR Cryoelectronics

Stirling Cryogenics, a brand of DH Industries

Stöhr Armaturen GmbH & Co. KG

Sumitomo (SHI) Cryogenics of America, Inc.

Sunpower, Inc.

SuperPower Inc.

Technifab Products, Inc.

Temati

Tempshield Cryo-Protection

Thermax, Inc.

Thomas Jefferson National Accelerator Facility

TRIUMF

TS Italia SRL

V2 Flow Controls

Valcor Scientific

WEKA AG

Wessington Cryogenics, Ltd.

Cold Facts | April 2015 | Volume 31 Number 2 www.cryogenicsociety.org5

Inside This Issue

ON OUR COVEROur cover shows the South Pole Telescope polarization focal plane during initial deployment in early 2012. Image: Jason Austermann

COLUMNS SPOTLIGHTS

12

12

12

2212

STAR Cryoelectronics

V2 Flow Controls

shirokuma GmbH

Master Bond

Bürkert Fluid Control Systems

6

14

28

13

23

32

Executive Director’s Letter

Defining Cryogenics

Space Cryogenics

Kryo Kwiz

Cold Cases

Cryo-Oops

PEOPLE & COMPANIES

CALENDAR

47

49

FEATURES

Developments We Most Wish to See

Technology Focus: Cryocoolers and Cryostats

25

20

Letter to the Editor: Dennis Howland Retires

How Lab-Based ADR Cryostats Support Our Quest to Understand the Universe

7

16

First Annual FCC Held in Washington DC10

Featuring Women in Cryogenics and Superconductivity

Product Showcase

YouTube Campaign Supports #mylinearcollider

38

42

44

Research and Development of Large-Scale Cryogenic Air Separation in China34

Simulation of a Helium Dewar Using No Liquid Cryogens8

20

8

16

28

44


Cold Facts Magazine

Executive EditorLAURIE HUGET

EditorKELSEY BEACHUM

Advertising CoordinatorKIM DURDEN

Online Marketing ManagerJO SNYDER

CSA Board of Technical Directors

ChairmanJOHN WEISEND II

European Spallation Source (ESS)46 46-888 31 50

PresidentJAMES FESMIRE, NASA Kennedy

Cryogenics Test Laboratory | 321-867-7557

Past PresidentAL ZELLER

FRIB, MSU | 517-908-7395

President-ElectMELORA LARSON, Jet Propulsion Laboratory

818-354-8751

TreasurerRICH DAUSMAN, Cryomech, Inc.

315-455-2555

SecretaryJONATHAN DEMKO

LeTourneau University

Executive DirectorLAURIE HUGET

Huget Advertising, Inc. | 708-383-6220 x 302

Registered AgentWERNER K. HUGET, Huget Advertising, Inc.

Technical Directors

KATHLEEN AMM, GE Global Research

LANCE COOLEY, Fermi National AcceleratorLaboratory

VINCENT GRILLO, Cryofab, Inc.

TERRY GRIMM, Niowave, Inc.

PETER SHIRRON, NASA GoddardSpace Flight Center

JOE SNYDER

WILLIAM SOYARS, Fermi National Accelerator Laboratory

SIDNEY YUAN, The Aerospace Corp.

Welcome to the second issue of 2015. We’ve reached out success-fully to our members to

bring fresh, pertinent content to Cold Facts. We think it enriches the reading experience and is indicative of the scope of our reader/member base.

We are hard at work planning for the upcoming Space Cryogenics Workshop (SCW), to be held June 24-26 at the Embassy Suites Phoe-nix-Biltmore. Be sure to register be-fore May 1 to get the early discount. And make your hotel reservation by May 27 to get the special discounted rates. This year we are also offering optional tours right after the work-shop. See the “Tours” page of the SCW website (http://2csa.us/tours) for information and to sign up.

We have an exciting roster of instructors for our Short Courses, to be held on Sunday, June 28, just before the start of the Cryo-genic Engineering Conference/International Cryogenic Materials Conference (CEC/ICMC), at the Marriott Starr Pass Resort, Tucson. The great team of Ray Radebaugh and Ron Ross will be teaching a full-day course called “Cryocooler Fundamentals and Space Applica-tions.” This dynamic duo will bring some serious expertise to the topic. We’re also presenting two half-day courses. We will again offer “Practi-cal Thermometry and Instrumenta-tion,” an invaluable and important course taught by Scott Courts, who

is an authority on this subject. We’re welcoming another new instructor who will teach “Superconducting Radio Frequency Systems,” Rong-Li Geng. Students will get a grasp of the major issues and technology of SRF, an extremely timely topic.

Werner Huget and I plan to attend the annual meeting of the Compressed Gas Association in mid-April, at the association’s in-vitation. We hope to expand our contacts and knowledge of what’s going on in the areas of industrial gases.

We look forward to our next issue, Cold Facts Volume 31 Num-ber 3, which will feature cryogenic vacuum technology; an update on helium sources, liquefaction and uses; superconducting energy trans-mission and storage; a technology focus on valves and pumps; and tributes to CSA Fellow Dr. Thomas Flynn, who passed away on March 16.

Volume 31 Number 4 will fea-ture cryotechnology for LNG trans-portation, storage and distribution; an ITER update; some young faces in cryogenics and superconduc-tivity; reports on SCW and CEC/ICMC; and a technology focus on cryogenic piping, transfer lines, fit-tings and connectors.

We invite you to submit content on these topics so we can continue our plan to include our readers and members in the fabric of Cold Facts.

Although CSA makes reasonable efforts to keep the information contained in this magazine accurate, the information is not guaranteed and no responsibility is assumed for errors or omissions. CSA does not warrant the accuracy, completeness, timeliness or merchantabil-ity or fitness for a particular purpose of the information contained herein, nor does CSA in any way endorse the individuals and companies described in the magazine or the products and services they may provide.

From the Executive Director

Randall Barron, ret. Louisiana Tech UniversityJack Bonn, VJ Systems, LLCRobert Fagaly, Quasar Federal Systems; SPAWARBrian Hands, ret. Oxford UniversityPeter Kittel, ret. NASA Ames Peter Mason, ret. Jet Propulsion Lab

Editorial BoardGlen McIntosh, McIntosh CryogenicsJohn Pfotenhauer, University of Wisconsin-MadisonRay Radebaugh, ret. NIST BoulderRalph Scurlock, Kryos Associates, ret. University of SouthamptonNils Tellier, NTCI, a Division of EPSIM Corp.

Cold Facts (ISSN 1085-5262) is published six times per year by theCryogenic Society of America, Inc.Contents ©2015 Cryogenic Society of America, Inc.


Letter to the Editor: Dennis Howland Retires

Dear Werner and Laurie:

As you probably already know, I have sold my company, DLH Industries and the Cryocomp product line, to Cryo-fab Inc. of New Jersey. It took me a couple of years to make the decision to sell and after discussing possibili-ties with several companies in the industry, Cryofab surfaced as the best choice in my opinion. They work hard, are very customer-oriented and are just good people.

My personal experience in cryo-genics has covered a span of more than 40 years if you count my almost first job out of college testing 8" ball valves for Rocketdyne in the mid ’60s and later designing relief valves for Anderson Greenwood into the ’70s.

I got involved with CSA and began attending the cryogenic meetings during my tenure at Cryolab sometime in the early ’80s. At the CEC/ICMC and ASC confer-ences I met a number of amazing, friendly and great people from many corners of the industry, companies big and small, engi-neers, lab techs, machinists, managers and consultants, many of whom I hope to main-

tain contact with and consider personal friends and mentors.

One of my favorite experiences, other than getting frostbite on my toes during a valve test that went awry, was becoming a part of the Cryo Mafia, which brought many like-thinking individuals together, mostly for the purpose of discussing food

and drink and usually a little tech-nical discussion to keep the tax guy happy. They are a very social lot.

The cryogenics industry is an extremely close-knit community and I am pleased to have been a thread in that fabric and hopefully contributed something of lasting value. To any-one who would like to stay in touch, my email is [email protected].

Regards,

Dennis HowlandPresident RetiredDLH Industries

CSA received the following letter from Dennis Howland, formerly presi-dent of DLH Industries.

[email protected]

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Fifty milliKelvin, now that’s cold! This is the temperature at which the detector array aboard the soft X-ray detector (SXS), destined for the Japanese Astro-H mission, is held when gathering X-rays. This detec-tor is capable of sub-5 eV resolution and is state-of-the-art at the time of this writing [1].To achieve this amazing feat, the detec-tor array must be cooled to 50mK. This is done by connecting it to the coldest stage of a multi-stage adiabatic demagnetization refrigerator (ADR).

This ADR, developed by the Cryogen-ics and Fluids Branch at NASA’s Goddard Space Flight Center, is capable of holding the detector array at 50mK for greater than 24 hours with better than 2μK stability over a 10-minute period [2]. After its cooling capacity is expended, the refrigerator may recycle to either a pumped helium bath at

1.2K or a 4.5K Joule-Thomson cooler. These two heat sinks allow a great deal of flexibil-ity and fault tolerance.

The capabilities and performance of the ADR system are covered elsewhere [2]. What has not been described before is the ground-based system used to test both the engineering and flight models of the ADR and detector array. To fully test the ADR, a cryostat that simulates both heat sinks found in the cooling chain of the flight unit is needed. Therefore, both a 1.2 and 4.5 Kel-vin interface are required in any simulation of the flight dewar. The higher temperature is achieved using a commercial off-the-shelf cryocooler. The lower temperature may be achieved using a helium-4 bath evacuated until the vapor pressure is below 82 Pa (about 0.6 Torr). However, a helium bath requires periodic refilling during a testing campaign. To perform the refill the bath needs to be warmed to 4.2K, additional liquid helium must be added, and then the bath must be pumped back to operating pressure. To avoid this additional labor, and the associated attention necessary when using sub-atmospheric liquid helium, it was decided early in the program that the helium tank would be simulated using a 2-stage ADR with the same 4.5K cryocooler already required for the higher temperature heat sink mentioned above.

An ADR uses the magneto-caloric ef-fect to cool to low and ultralow tempera-tures. Simply put, when a paramagnetic substance—typically a pill containing a salt with the proper magnetic characteristics for a given operating temperature range—is subjected to an increasing magnetic field, the individual magnetic moments will align. This alignment lowers the entropy of the paramagnetic material, and energy is liber-ated in the form of heat. If the pill within the ADR stage is connected to a heat sink at a lower temperature, heat will flow out of the pill while the entropy of the paramagnetic system decreases. After an upper field is reached, the thermal link between the salt pill and the heat sink is opened. A reduction of the magnetic field permeating the salt pill will cool the pill along with anything attached to it—such as a detector array. When the desired operating temperature is reached, one controls the rate of reduction in the magnetic field such that the entropy

change in the pill matches the heat coming from the detector array. The end result is a constant ultralow temperature of the array.

To mimic a helium tank with an ADR, one first brings the interface acting as the helium tank to a fixed low temperature, say 1.2K, using an ADR stage. Then one controls the demagnetization rate such that any heat imposed on the tank is taken up by the ADR system. Therefore, the helium tank is held at a constant temperature as long as the ADR has cooling capacity in excess of the heat flowing into the tank.

For this system, we have built an ADR with two stages. Both stages use gadolinium gallium garnet as the paramagnetic mate-rial. This choice of material is based upon the ease of procurement and relatively low cost (it is used as an optical or laser crystal). It also has magnetic characteristics so that it works well in the 1.2 to 4.5K range.

This two-stage ADR may be configured in one of two ways. The first uses one stage as an active thermal ballast while the other stage rapidly cycles between the helium tank and cryocooler temperatures. This pulls heat from the helium tank and transfers it to the higher temperature cryocooler. When not transferring heat to the cryocooler, the cycling stage, Stage B, attempts to cool the helium tank below the tank temperature setpoint. However, the ADR stage directly coupled to the helium tank simulator, Stage A, compensates by magnetizing and add-ing heat to the tank to maintain a constant

Simulation of a Helium Dewar Using No Liquid Cryogensby Dr. Mark O. Kimball, NASA/Goddard Space Flight Center, [email protected]

Figure 1: The dewar containing the cryostat built specifically for testing the Astro-H detector array and ADR. During assembly, the dewar is rotated upright. During operation, it is rotated horizontal to the ground to allow the pulse tube of the cryocooler to align vertically.

Figure 2: A two-stage ADR provides the cooling for the “helium tank.” The two stages are on the right side in the photo (one hidden behind the other), the heat switches are on the left, and the bottom of the helium tank is seen in the upper portion of the photo.


temperature. When Stage B depletes its cooling capability it decouples from the helium tank via a heat switch. At this point, Stage A must decrease the current in its associated magnet to pull incoming heat from the helium tank. Simultaneously, the cycling stage recycles by lifting its stored heat to the cryocooler. After the recycle finishes, the second stage lowers its temperature below the helium tank’s setpoint and the thermal link between Stage B and the tank is made via the heat switch. Stage A again compensates to keep the temperature constant by increasing the field in its magnet. This cycle continues until the testing campaign is over.

The second configuration is one where both stages cycle as quickly as possible in a manner that is synchronous but out of phase by 180 degrees. Here, one stage is lifting heat to the cryocooler while the other is controlling the temperature of the tank. This configura-tion trades temperature stability for additional cooling power. This allows the temperature of the tank to be lower than configuration [A] but with larger temperature fluctuations.

A plot of the temperature of the helium tank, Stage A and Stage B during multiple ADR cycles is shown in Figures 3b and 4b. Compar-

Figure 3: ADR configuration [A]. Here, the tank temperature is controlled by ADR Stage A, while Stage B periodically pulls heat from the tank and lifts it to the cryocooler.

Temperature profile of the helium tank, ADR Stage A and ADR Stage B during operation.

Temperature profile of the helium tank, ADR Stage A and ADR Stage B during operation.

ing both plots, one finds a higher tem-perature stability for configuration [A] in Figure 3 but with a higher overall tank temperature. The opposite is seen for configuration [B] in Figure 4. One could merge the two configurations into a system that combines the posi-tive attributes of both. This would be accomplished by adding a third stage to configuration [B] that would act as an active thermal ballast to smooth out the temperature fluctuations dur-ing handoff of control of the helium tank from one of the other two stages. Another method of smoothing the temperature disturbances is to utilize a feed-forward control of both ADR stages, but this is a topic for another time.

So, it is possible to simulate the environment offered by a liquid he-lium dewar without using a liquid cryogen. The cryostat described here simulates the environment that the in-strument developed by NASA for the Astro-H mission will experience when it gazes into outer space. Over the past few years this cryogen-free cryostat was used to test both the engineering and flight models of the Astro-H ADR and detector assembly. At the time of this writing, the flight ADR and detec-tor assembly are being integrated into the spacecraft at the Japanese Aero-space Exploration Agency facility in Tsukuba, Japan.

References1. F. S. Porter, J. S. Adams, G. V. Brown,

J. A. Chervenak, M. P. Chiao, R. Fuji-moto, Y. Ishisaki, R. L. Kelley, C. A. Kilbourne, D. McCammon, K. Mit-suda, T. Ohashi, A. E. Szymkowiak, Y. Takei, M. Tashiro, and N. Yamasaki. The detector subsystem for the SXS instrument on the ASTRO-H Obser-vatory. In Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, volume 7732 of Society of Photo-Optical Instrumen-tation Engineers (SPIE) Conference Series, page 3, July 2010.

2. P. J. Shirron, M. O. Kimball, B. L. James, D. C. Wegel, R. M. Martinez, R. L. Faulkner, L. Neubauer, and M. Sansebastian. Design and predicted performance of the 3-stage ADR for the Soft-X-ray Spectrometer instru-ment on Astro-H. Cryogenics, 52(4-6, SI):165-171, Apr-Jun 2012.

Figure 4: ADR configuration [B]. Here, both stages alternate between controlling the temperature of the tank temperature and transferring heat to the cryocooler.

3a

4a

3b

4b


The meeting began with a presentation by US congressman Bill Foster, who recalled the past his-tory of the LHC as well as the former design studies for a Very Large Hadron Collider. He encouraged the high energy physicists in the audience to “never be shy in standing up for the unique nature of their field and never be afraid of big numbers.” A special session on Thursday was devoted to the experience with the US LHC Accelerator Research Program, to the US particle physics strategy and to US R&D activities in high field magnets and su-perconducting radio frequency. A well-attended industrial exhibition and a complementary “indus-try fast-track” session were focused on Nb3Sn and high temperature superconductor development.

James Siegrist from the US DOE pointed the way for aligning the high field magnet R&D ef-forts at the four leading US magnet laboratories (Brookhaven, Fermilab, Berkeley Lab and the Na-tional High Magnetic Field Laboratory) with the goals of the FCC study. An implementation plan for joint magnet R&D will be composed in the near future. Discussions with further US institutes and universities are ongoing, and within the coming months several other DOE laboratories should join the FCC collaboration. A first US demonstrator magnet could be ready as early as 2016.

FCC study leader Benedikt pointed out that 2015 should be the year in which the worldwide collaboration reaches consensus on the baseline pa-rameters and concepts and fleshes out the collider layout and injector and infrastructure concepts. “It is time to put a Nb3Sn 16 T magnet program on solid feet, to define and launch other selected technology R&D programs,” he said.

The next FCC week will be held in Rome on April 11-15, 2016. ■

The CERN Courier reports that some 340 partici-pants from science and industry attended the first global Future Circular Collider (FCC) week in Washington DC March 23-27 to discuss the study status and plans for the future.

The proposed FCC accelerator ring would be 100 kilometers around and run at 100 TeV center of mass energy. A total of 219 contributions from all areas of the study showcased both the progress achieved and the challenges ahead. The FCC week covered all aspects of the study—designs of 100-km hadron and lepton collid-ers, infrastructures, technology R&D, experiments and physics. Geology studies are also underway for siting the FCC in a tunnel near Geneva, Switzerland, linked to CERN. A total of 51 institutes have joined the FCC collaboration since February 2014 and the FCC study has been recognized by the European Commission.

Jointly organized by CERN and the US DOE with support from the IEEE Council on Superconductivity (CSC), the week was organized by Dr. Bruce Strauss (DOE), Dr. Michael Benedikt (CERN) and Dr. Frank Zimmermann (CERN). Local arrangements were handled by Suzanne Strauss for the CSC. More than a third of the participants (120) came from the US. CERN (93), Germany (20), China (16), UK (16), Italy (12), France (11), Russia (11), Japan (10), Switzerland (10) and Spain (6) were also represented. For further information, visit www.cern.ch/fccw2015.

First Annual FCC Week Held in Washington DC

Image: Luca Bottura, CERN

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SPOTLIGHT ON SUSTAINING MEMBER


Bürkert Fluid Control Sys-tems has won the 2015 Golden Gas Award from the US maga-zine Gases & Instrumentation International for the company’s new Type 8741 mass flow con-troller (MFC)/mass flow meter (MFM). The MFC/MFM features a standardized interface for real-time communication with the proprietary Bürkert system bus (büS). The system control unit Type ME2X can control up to 16 büS devices and functions as a gateway between industrial ethernet and the büS. Bürkert Communicator software

enables intuitive parameterization of the MFC/MFM and allows convenient process control. If a CAN bus already exists, a toggle switch on the device can

be used to switch between büS and CANopen.

G&I covers the technology and application of industrial, specialty and medical gases. The Golden Gas Awards are judged by a panel of independent techni-cal experts not affiliated with any product or manufacturer. Prod-ucts are rated on ability to solve an important challenge to the gas industry, such as technological

innovation, superior specifications in terms of power requirements, speed, maintenance and other quality consid-erations. www.burkert.com

Bürkert Receives 2015 Golden Gas Award

SPOTLIGHT ON NEW SUSTAINING MEMBERS

STAR CryoelectronicsSTAR Cryoelectronics, founded in

1999, is a leading supplier of advanced LTS and HTS dc SQUID sensors, cryo-cables, PC-based SQUID readout elec-tronics, TES microcalorimeter and STJ X-ray detectors, and two-stage SQUID amplifier readouts for cryogenic detec-tors. It also produces the popular Mr. SQUID® educational demonstration system.

The company offers extensive cus-tom LTS and HTS thin-film design and foundry services for a wide range of su-perconducting electronics applications. STAR Cryoelectronics also offers turn-key, cryogen-free ADR cryostats with cooling to 50mK, TES microcalorimeter spectrometers for X-ray microanalysis, and STJ X-ray absorption spectrometers for synchrotron science applications. www.starcryo.com

shirokuma GmbHshirokuma GmbH provides cryo-

genic expertise, prototype construction for cryogenic components and practical problem-solving for technology devel-

opment for research institutions and industrial partners. Customers will benefit from their longstanding practi-cal experience in cryogenics and their expertise in hydrogen as energy-carrier technology, in cryogenics and at pres-sures up to 1000 bar.

shirokuma GmbH links science and industry by connecting with experts from Swiss and international research organizations and with industrial com-panies in cryogenics. In cooperation with a qualified engineering company, shirokuma GmbH maintains a suppli-ers network with the latest manufactur-ing and joining technologies, including additive manufacturing in metals and plastics. The company offers sizing cal-culations for control valves and process components and for processes based on the CONVAL® software tool with inte-gral property database for gases and liquids. www.shirokuma-gmbh.ch

V2 Flow ControlsAn authorized full service dis-

tributor of Sponsler, V2 Flow Controls has the knowledge and capability to

support customers in the cryogenic industry. Whether transporting, load-ing or delivering, Sponsler cryogenic measurement systems are specifically designed and tested to thrive in harsh industry conditions. Incorporating the Sponsler Precision Turbine Meter and selecting an electronic or mechani-cal register allows users to assemble a cryogenic measurement system per-fectly suited to their needs.

The T675 Cryogenic Flow Totalizer, Sponsler’s electronic register designed specifically for cryogenic applications, provides a comprehensive array of transaction, metrological, security and maintenance options so users can tailor their cryogenic measurement system according to their operations. Spon-sler cryogenic measurement systems are available in volumetric and mass configurations that provide precision performance in both cryogenic and ambient temperatures. The systems are designed and certified to meet or exceed the requirements stated in NIST Handbook 44 as well as OIML R81, OIML R117-1 and MID. www.v2flowcontrols.com ■

CSA Welcomes Newest Corporate Sustaining Members


by Dr. Glen McIntosh, McIntosh Cryogenics, CEC Collins Awardee, CSA Fellow, [email protected]

Kryo Kwiz

Below is a problem and its solu-tion from one of the past editions of our monthly e-newsletter,

CryoChronicle.

Question: Kryowhiz designed a 1.8K superfluid liquid helium dewar for a space launch. Its heat leak was low, but Kryowhiz was concerned that a few hours of hold time on the launch pad might cause it to start venting. Frosty suggested a simple procedural change to extend the no-loss time on the launch pad.

What was his suggestion?

Answer: Frosty noted that the maximum density of liquid helium is at the 2.172K Lambda point and density falls somewhat down to about 1.5K and is practically constant to lower tem-peratures. Thus, cooling the load on the launch pad from 1.8K down to 1.5K or colder would allow the liquid to warm up all the way to the Lambda point without venting.

a

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Could you have answered this question correctly? Look for the Kryo Kwiz every month in our CryoChronicle e-newsletter. Subscribe at www.cryochronicle.com.


by Dr. John Weisend II, European Spallation Source, CSA Chairman, [email protected]

Defining Cryogenics

Air separation is one of the larg-est, as well as earliest, indus-trial applications of cryogenics.

In this process, cryogenic temperatures are used to separate air into its constitu-ent gases: nitrogen (78.08%), oxygen (20.95%), argon (0.93%) and carbon di-oxide (0.3%). Trace gases such as kryp-ton, neon, xenon and helium total far less than 1%. Water vapor can also be a sig-nificant fraction of air but it is removed along with carbon dioxide at the start of the separation process.

The components of air have many applications in industry and research, and the separation, transport and selling of these gases is a multibillion dollar in-dustry. Air separation is a principal part of the business of large industrial gas firms such as Air Products, Air Liquide, Linde and Praxair.

There are essen-tially two production models used in the air separation industry. In the first, centralized plants separate the air and the resulting components are then shipped to customers offsite, frequently in the form of cryogenic liquids. In the sec-ond, an air separation plant is located at the customer site itself to produce, for example, oxygen for a chemi-cal plant or steel mill or nitrogen for use in pressurizing oil fields to increase recovery. The remaining gases not of direct interest to the customer are either sold to other customers

or vented to the atmosphere, depending on the economic case. Air separation plants are quite large, with typical ca-pacities being thousands of tonnes per day of oxygen and nitrogen produced.

Cryogenic air separation is based on the principle of rectification, which is defined in Barron as “the cascading of several evaporations and conden-sations carried out in counterflow.” A simple version of this is shown inFigure 1. Air is compressed and all of the water, hydrocarbons and carbon dioxide are removed. The resulting air is cooled down via heat exchange with colder flows of nitrogen and oxygen and then expanded via both expansion engines and valves to near the saturation tem-

perature of oxygen and nitrogen. This cold, near-saturated mixture is then fed into the rectification column. Since oxy-gen has a higher boiling temperature than nitrogen, as the mixture progresses through the trays or plates of the col-umn, the liquid portion, which flows down, becomes progressively richer in oxygen, while the gas portion, which flows up, becomes progressively richer in nitrogen. The liquid oxygen at the bot-tom of the column still contains signifi-cant amounts of nitrogen, while the gas at the top is almost pure nitrogen, with small fractions of argon, xenon, helium, etc. In the example given, the plant was designed only to produce crude oxygen and the nitrogen flow is vented. Many complicated variations on this technique

Figure 1 Schematic of a liquid oxygen plant. Image: Mechanical Engineers’ Handbook, Vol. 4, M. Kutz (Ed). Copyright © 2015 Air Liquide. Reproduced with permission of John Wiley & Sons, Inc.

Air Separation


exist. One of the most common uses two rectification columns placed on top of each other, operating at different pres-sures. This arrangement (known as the Linde double-column system) results in the production of much higher purity oxygen and nitrogen. Additional col-umns can be added to remove argon, xenon, krypton and neon.

In all cases, the systems make judi-cious and clever use of colder mixtures to precool warmer mixtures and of warmer flows to boil off gas from colder mixtures. The rectification columns and their associated heat exchangers and valves are generally referred to as air separation units in the industrial gas industry.

Helium can be separated from air, but it is far more cost effective to sepa-rate it from natural gas fields where it can occur in percentages greater than 1%, as opposed to only 0.0005% in air. A very large helium liquefier plant has

recently been built in Qatar to liquefy the helium extracted from the natural gas fields.

The need for air separation plants to compress and move thousands of tonnes of air a day means that they require significant amounts of energy. Thus, a number of energy recovery schemes are typically used, including using the work done by the gas on the expansion engines to help power the compressors. Research on modeling and optimizing the rectification columns and heat ex-changers to improve the product purity while reducing energy consumption is ongoing.

Additional details on cryogenic air separation may be found in Cryogenic Engineering, R. Barron, McGraw-Hill (1966); Separation of Gases, W. H. Isalski, Oxford University Press (1989); and “Air Separation Plant Design,” D. J. Hershand J. M. Abrado, Cryogenics (July 1977). Examples of modeling of air separation

plant components include “Simulation of Multistream Plate-Fin Heat Exchangers of an Air Separation Unit,” R. Boehme et al., Cryogenics 43 (2003) and “Hybrid Model of Structured Packing Column for Cryogenic Air Separation,” Z. Wu et al. Proc. ICEC 24 (2013). An example of using heat recovery to reduce energy use in air separation plants is presented in “A Novel Cryogenic Air Separation Process Based on Self-Heat Recupera-tion,” Y. Kansha et al., Separation and Purification Technology 77 (2011). The relative merits of cryogenic air separa-tion and pressure temperature swing adsorption techniques are discussed in “Comparative Analysis of Cryogenic and PTSA Technologies for Systems of Oxygen Production,” T. Banaszkiewicz et al. in Adv. Cryo. Engr. Vol 59b (2014). A description of the Air Liquide helium liquefier built in Qatar may be found in “Ras Laffan Helium Recovery Unit HeRUII Project,” R. Ali Said et al., Proc ICEC 2014 (at press). ■

TECHNOLOGY FOCUS


Cold Facts asked our members in the field of cryocoolers and cryostats to weigh in on the technology’s most important developments, significant contributors and anticipated future advances. Here is a roundup of their replies.

Most important developmentsRay Radebaugh (ret. National Insti-

tute of Standards and Technology) ranks multilayer insulation (MLI) among the most important developments in cryocool-ers. “MLI is now used everywhere in low loss dewars and in cryocoolers for mini-mizing heat leak,” he said. “It is also used for thermal control in spacecraft. Dewar heat leaks were reduced by about an order of magnitude compared with the powder insulations used before MLI came on the scene.”

Radebaugh also included Gifford-McMahon cryocoolers as an important de-velopment, as they have been “the work-horse cryocooler for a very wide range of applications ranging from cryopumping, MRI systems and many R&D applications. The development of rare earth materials helped them expand their applications to the 4K range.”

Alan Caughley (Callaghan Innova-tion) listed the Gifford-McMahon cryo-cooler as well. “This really was the first useful cryocooler and started [the] use of cryocoolers instead of liquid cryogens,” he said. “It opened up the possi-bility of a dial-up temperature and has been the workhorse of the industry for 50 years.”

Many of our respondents consider the pulse tube cryo-cooler an important develop-ment. “Pulse tube cryocoolers have been extremely popular for the last decade or so for both commercial and space applications,” said Radebaugh. “Research on them continues today as the most studied cryocooler because of the lack of cold moving parts and the wide range of improvements that are possible. 4K pulse tube cryocoolers are having a major im-pact on eliminating the use of scarce liq-

uid helium on many 4K experiments and applications.”

“The development of pulse tube cryo-coolers has been one of the major advances in the past three decades that has helped expand the use of cryocoolers in both ground and space applications,” said Ali Kashani (Atlas Scientific).

“In my own narrow specialty of linear-motor-driven pulse tube cryocool-ers,” said Philip Spoor (Chart, Inc., a CSA CSM), “one could argue that the single most important development, which al-lows us to be more productive every day, was the development of computer codes that model these devices accurately enough to make reasonable predictions about what they’ll do. This applies espe-cially to the widely used computer codes Sage and DeltaE, because they enable col-leagues to share information and designs more readily than if everyone is using their own codes.”

Peter Kittel (ret. NASA Ames) cited the invention of the orifice pulse tube, explaining, “This cryocooler was vastly more efficient than the original, basic pulse tube. Its efficiency was high enough that it could [be] put to practical use and it has been in medical, industrial and space applications.”

“The pulse tube implementation of the Stirling thermodynamic cycle with no moving parts, as pioneered by Ray Rade-baugh, enables smaller, long life space cryocoolers at higher temperatures,” said Dale Durand (Northrop Grum-man Aerospace Systems). He considers

the Oxford-type linear compressor to be equally important for higher temperature space cryocoolers. Durand also listed the adiabatic demagnetization refrigerator for low temperatures as another significant development. “The ability of the magnetic field to interact with the spin temperature without a thermal parasitic enables fan-tastically low temperatures in a relatively small device,” he explained.

Others also listed developments per-taining to space. “The development of a spaceflight cryocooler that lifts 20 W at 20K is an important development for cryocoolers in recent years,” said Shuvo Mustafi (NASA Goddard). He continued, “The development of advanced MLI that uses polymer spacers instead of netting used for conventional MLI could enable a number of cryogenic storage and transfer options for cryostats.”

Jason Hartwig (NASA Glenn Re-search Center) cited another recent devel-opment, the demonstration of zero boiloff (ZBO) for liquid oxygen at 91K for an indefinite time. “All future manned space applications (including large upper stages, cryogenic fuel depots, sample return mis-sions and ascent stages) will benefit from zero (not reduced) boiloff of the cryogen. Having recently demonstrated that we can store a 90K cryogen indefinitely represents

a huge impact in cryocooler technology development.”

“The most important ad-vancement in cryocoolers from my perspective, that being the storage of cryogenic propel-lants,” said David Plachta (NASA Glenn Research Cen-ter), “is the NICMOS reverse turbo-Brayton cycle machine. This flight cryocooler and its derivatives offer the potential to eliminate propellant boil-off in space, enabling depot concepts and human missions

architecture plans being considered by NASA.”

Important contributorsRadebaugh recognized a number of

important contributors to cryocooler and

Cryocoolers and Cryostats

An “antique” Cryomech pulse tube cooler from 1965 Image: M. Bradley


one of the key scientists in the develop-ment of pulse tube cooler technology,” said Kashani. “He has been instrumental in advancing our understanding of the physics of pulse tube coolers as well as de-veloping analytical and experimental tools to study these coolers. He has also helped in educating and training many of the sci-entists working on pulse tube coolers.”

“Ray Radebaugh deserves much credit for advancing the field and educat-ing/guiding so many professionals mak-ing additional advances,” Durand agreed.

Kittel also cited E. I. Mikulin, as well as A. A. Tarasov and M. P. Shrebyonock, authors of the paper “Low-temperature expansion pulse tube,” Adv Cry Eng 29 (1984), p. 629. “This is the first paper descri bing the orifice pulse tube,” he ex-plained. “It showed a significant advance over the basic pulse tube (1963) of Long-sworth and Gifford. By 1983, almost all interest in pulse tubes had died because the basic pulse tube was very inefficient… [and] never found a practical application. This paper reinvigorated the field, show-ing an efficient pulse tube could be devel-oped, which led to the rapid developments of the ’80s and ’90s.”

“Because of their special importance of common language to collaboration,” said Spoor, “I would single out David Gedeon (of Gedeon Associates), creator of the Sage software package, and Greg Swift and Bill Ward (of Los Alamos National Laboratory), creators of the DeltaEC soft-

ware package. Their contributions include not just the software for modeling cryo-coolers, but the documentation that gives excellent basic instruction in the relevant physics. Their codes are also useful for modeling many other mechanical, acoustic and thermal devices besides cryocoolers.”

Mustafi and Plachta both credited Creare, Inc., which is working to develop a spaceflight cryocooler that lifts 20 W at 20K. Plachta cited the company and “its lead technologist, Mark Zagarola, as being the driving force behind this advance.”

Hartwig recognized Mark Zaga-rola and Dave Plachta.

Mustafi also named Quest Thermal Group, which he said is developing advanced MLI insulation under guidance from NASA.

Caughley’s picks were “Bill Gifford of course, then Peter Gifford for building the busi-ness. Chao Wang sits quietly behind Cryomech and has been the source of its recent technical success.”

Future developmentsOur member panel hopes to

see a variety of developments in cryocooler and cryostat technol-ogy in the future.

“MLI has one disadvantage in that it is difficult to apply,” said Radebaugh. “Something easier to apply and at a lower cost would be a great improvement.” He continued, “Variable speed drives for GM compressors are beginning to be introduced now. I also would like to see increased efficiencies and reduced noise from these compressors.

“A significant development in pulse tubes would be that of really miniature pulse tube cryocoolers employing much higher frequencies, warm displacers, and a regenerator packing with very small hydraulic diameter,” Radebaugh contin-ued. “Another important need is 4K pulse tube cryocoolers with Carnot efficiencies considerably higher than 1 percent, which could be possible with a much better un-

cryostat technology. “Several people and institutions appear to have been respon-sible for the development of MLI,” he said. “An entire session of the 1959 CEC (Vol. 5) was devoted to MLI as it suddenly ex-ploded on the scene in about 1958-1959. P. Peterson of the University of Lund in Sweden is credited with the concept of multilayers of aluminum foil and glass wool spacers that had remarkable insulat-ing qualities. His work occurred in 1951 but was not noticed much until several years later. Some leaders in the 1958-1959 development period were R. H. Kropschot of NBS in Boulder, L. C. Matsch of Linde-Union Carbide Corpo-ration and M. P. Hnilicka of NRC Equipment Corporation.

“As the name indicates,” Radebaugh said, “William Gif-ford and Howard McMahon were the important figures in the development of the Gifford-McMahon cryocooler. Gifford was the leader in the innova-tions and the technical input and McMahon was the driving force behind the commercialization of the cryocooler. The introduction of spherical rare earth powders by Toshiba and the pioneer-ing 4K work by T. Kuriyama of Toshiba were instrumental in the development of 4K GM and GM-type pulse tube cryocoolers.

“William Gifford was also an impor-tant figure in the development of pulse tube cryocoolers,” Radebaugh added. “Even though the type he developed was not successful for cryogenic temperatures, he introduced the concept of the empty tube in the 1960s, the “pulse tube” that laid the groundwork for the later version to come in the early 1980s in which an orifice was introduced to the system by E. I. Mikulin. Many improvements have been made since then by many people. The field of thermoacoustics has greatly matured as a result of the pulse tube cryo-cooler and related thermoacoustic devices, due in large part to Greg Swift. 4K pulse tube cryocoolers have become very suc-cessful because of the pioneering work ofG. Thummes and C. Wang.”

Other cryocooler experts cited Rade-baugh himself as an important contributor to the field. “Dr. Ray Radebaugh has been

Dr. Ray Radebaugh with a pulse tube cryocooler. Image: NIST Boulder

(Continued on page 18)


derstanding of the losses at 4K in regen-erators and pulse tubes.”

Kashani noted, “Advancing regenera-tor technologies to improve efficiency of pulse tube coolers is one area that would be beneficial for many applications requir-ing cryogenic cooling.” Kittel also hopes to see increased efficiency, especially in the 4-10K range, as it would reduce depen-dence on helium as well as reducing the power consumption of superconducting machines.

“Of course I see hope in my work for the future, the metal diaphragm pressure wave generator coupled to a pulse tube or Stirling cold head,” said Caughley. “It is a really cost-effective and robust cryocooler for industrial uses.”

Spoor acknowledged that in the codes he considers to be an important develop-ment, one of their biggest limitations is that they are “essentially one-dimensional; they assume uniform pressure and flow

along the computation axis. In the future, it would be very exciting to see computa-tional fluid dynamics reach a state of ma-turity and speed of execution to enable us to look at 2- and 3-D effects in cryocooler designs, including the sensitivity of de-signs to small manufacturing flaws.”

Advances in cryocooler manufac-turing also interest Durand. “New 3-D printing-type manufacturing may enable us to break through the current limitations in the design trades between thermody-namic optimum solutions and structural requirements by allowing designs that are currently impossible to manufacture,” he said.

In the future, Plachta would like to see a high performing broad area cooled shield within the MLI that thermally insulates a LH2 propellant tank, as well as improve-ments to the modeling and prediction of cryocooler parasitic losses and the reduc-tion of those losses. Hartwig hopes to see

“ZBO LH2 demonstration, both on the ground and in flight. To those who have been working in cryogenics at NASA GRC for the past 30 years, this represents the top, key milestone in cryogenics: being able to store the highest efficiency propel-lant indefinitely.”

“The development of cryocoolers that lift 100-500 W at 90K, coupled with the20 W at 20K cryocooler, will allow for long-term ZBO active storage of cryo-genics propellants such as liquid hydro-gen and liquid oxygen,” said Mustafi. “The demonstration of advanced MLI on space flight missions and on large flight tanks with appropriate penetrations will increase the technology readiness level of these types of insulation to be used for long-term storage and transfer of cryogens. This technology, coupled with advances in subcooling technology, may even enable the long-term ZBO passive storage of cryogenic propellants such as liquid hydrogen and liquid oxygen.” ■

Technology Focus... Continued from page 17

TECHNOLOGY FOCUS


Astronomers and cosmologists are eternally curious about our universe. This curiosity motivates ever more sophisti-cated observation methods. Land-based telescopes continue to be one of the main instruments employed to study the sky.

The receivers (or cameras)—the part of the instrument where the light is converted to electrical signals—on these telescopes is where many of the advances in hardware are taking place. Some of the recent work has been concentrated on developing cryo-genic polarimeters and multi-chroic pixels. Scientists have developed large arrays of such detectors, which are extremely sensi-tive to light coming from the sky.

These advances are pursuing better measurements of the polarization and amplitude of the cosmic microwave back-ground (CMB) radiation. These improved measurements can lead to a more complete understanding of aspects of the universe such as neutrino physics, inflation and gravitational waves, to name just a few.

But long before these sensitive de-tector arrays are deployed in telescopes around the globe, years of development and testing occurs in the laboratory. Pro-totype components—including cryogenic detectors, feedhorn-waveguide assemblies and thevarious electronics—are placed into laboratory cryostats for characteriza-tion and testing.

The HPD Model 104 Olympus ADR cry ostat has been used extensively at the University of Colorado by the Center for Astrophysics and Space Astronomy (CU-CASA, one of the collaborating institutions working at the South Pole Telescope [SPT]). The most attractive feature of the Olympus cryostat is its large experimental volume. Inside the 3K radiation shield, scientists can take advantage of a volume measur-ing 17" in diameter and 23" in height. The Model 104 commonly configured is a two-stage adiabatic demagnetization refrig-erator (ADR) with base temperatures near 30mK, and typical operating temperature around 100mK.

How Lab-Based ADR Cryostats Support Our Quest to Understand the Universeby Charlie Danaher, Vice President, High Precision Devices, [email protected]

Section view of HPD Model 104 Olympus

A Fourier transform spectrometer being used to measure the spectral response of detectors located inside the Model 104 ADR cryostat at CU-CASA

South Pole Telescope (SPT). Image: Jason Austermann

SPT polarization focal plane during initial deployment in early 2012. Images: Jason Austermann


Hopkins University that will be deployed to a high-altitude site in the Atacama Desert as part of the Parque Astronómico de Ata-cama in 2015. The CLASS experiment aims to test the theory of cosmic inflation and distinguish between inflationary models of the very early uni-verse by making pre-cise measurements of the polarization of the CMB.

CLASS scientists at Johns Hopkins University have em-ployed the Model 104 ADR cryostat to test and guide the development of a new design of detectors that will eventually be employed in the CLASS telescopes.

In a just a few years, novel detector arrays currently being validated in the

Among the telescope observatories pursu-ing such research, and which have been either directly or indirectly supported by research at CU-CASA, are the SPT, a 10-meter-diameter telescope located at the Amundsen-Scott South Pole Station, Antarctica; the Atacama Cosmology Telescope (ACT), a six-meter telescope on Cerro Toco in the Atacama Desert in the north of Chile; and POLARBEAR, a CMB polarization experi-ment also located in the Atacama Desert.

Improved detector designs lead to compressed observation runs

One of the biggest pushes in detector ad-vancement is toward the goal of compressing observation time. If a telescope can collect the same amount of information as before but in a fraction of the time, or if more information can be gathered for a given observation period as compared to a previous setup, such improve-ment can both reduce exploration costs as well as bring closer a more complete understanding of the universe. Multi-chroic pixels, having several detectors each, multiply the amount of informa-tion gathered, for a given time period, without any cryogenic cost.

The Cosmology Large Angular Scale Sur-veyor (CLASS) is an array of microwave tele-scopes currently under construction at Johns

Model 104 hosting optical testing of detectors at John Hopkins University. Image: David Larson, CLASS collaboration

Computer-generated rendering of the future CLASS experiment deployed to a high-altitude site in the Atacama Desert of Chile. Image: CLASS collaboration

laboratory will see their first implemen-tation at these telescopes. Their observa-tion data will advance our knowledge of the structure and history of the universe. HPD is proud to contribute to this noble effort by providing physicists with the basic instruments needed to perform such exciting research. ■

SPOTLIGHT ON SUSTAINING MEMBER


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Supreme 12AOHT-LO is a thixotropic paste with a smooth consistency that is easy to handle. As a single component epoxy, it doesn’t require any mixing and offers an “unlimited” working life at room temperature. It cures rap-idly at elevated temperatures. This gray-colored system can be stored at ambient temperatures, but maxi-mum shelf life is achieved when

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Master Bond Supreme 12AOHT-LO Passes Testing for NASA Low Outgassing


by Dr. Bill Schwenterly, retired Oak Ridge National Laboratory, [email protected]

Cold Cases

Cryogenic installations often re-quire some sort of piping sys-tem that may have to operate

over a wide range of temperatures. The pipes may operate at room temperature, where they perhaps supply vacuum pumping and purging or pressuriza-tion to a dewar or cryostat, or provide helium gas connections between a com-pressor and a liquefier or refrigerator cold head. Some parts of the system may also have to provide heated gas for warming the equipment or regenerating purifier beds. Other parts may be carry-ing liquid cryogens or cold gas.

If pressure drops must be mini-mized, you will either need to make the installation as compact as possible to reduce the pipe lengths or use larger diameter piping. In earlier columns (see Cold Facts Volume 29 Number 3 and Volume 31 Number 1) I have discussed how to calculate pressure drops in gases or liquids for single-phase flow versus pipe length and diameter. For vacuum, the pipes need to be sized to give the desired pumpdown time and ultimate pressure. This is determined by the volume of the system, the speed of the available vacuum pump in the viscous and molecular flow regimes, and the expected outgassing rate of the internal surfaces. I’ll leave the details on select-ing vacuum piping sizes for another column.

In determining the layout of your system, be sure to think three-dimen-sionally. You want to have all attached equipment such as valves, instrumen-tation feedthroughs, vacuum jacket gauges and relief devices in accessible locations where you can easily operate and maintain them.

At ORNL I once worked with a young engineer who produced a beau-tiful set of drawings for the piping between a helium compressor and liq-

uefier. However, when the piping was installed, we found that several valves were located up near the ceiling and could only be reached with a steplad-der! In another case, we received a set of vacuum jacketed lines from a manufac-turer and discovered that several of the vacuum gauges on vertical runs were high out of reach where it was very dif-ficult to service their connecting cables or replace them when they failed. Ren-derings by modern 3-D CAD systems will help you avoid problems like this.

Piping that carries cryogenic gases or liquids will require thermal insulation for efficient operation. For temperatures near 77K, commercial piping with plas-tic foam insulation is usually the most economical option for large systems. For a small laboratory system, you can likely get away with foam rubber insu-lation sleeves like the ones used on air-conditioning lines. These can be easily formed around bends and secured with electrical tape. Fiberglass insulation sleeves are commercially available for hot gas systems.

For the lowest temperatures, vac-uum jacketed piping with multilayer insulation (MLI) reflective barriers is required. Check with prospective manu-facturers to find out the heat loads for rigid sections, flex sections and bayonet connections. Be sure to leave proper

clearances for the bayonets in assem-bling the system—you don’t want to get to the last piece and discover that you don’t have enough clearance to the wall to slide its bayonet into the mating fit-ting. Also keep in mind that most bayo-nets have the lowest heat load if they are installed with the male half pointing downward. Piping sections with bayo-nets that are at angles to each other are basically locked in place. If you can’t slide the equipment on either end of the piping away for disassembly, it’s a good idea to have a “U”-shaped piece in the system with parallel bayonets that can slide out easily to allow you to remove the other pieces.

All piping systems should have proper relief devices sized to prevent damaging overpressures. For cryogenic piping, it is particularly important to install thermal relief devices on all sec-tions that could be isolated between two valves, if both valves were closed with liquid or cold gas in the system, to pre-vent excessive pressures from develop-ing as the system warms up.

All joints and connections should be leak-checked carefully, preferably in subassemblies, before putting ev-erything together. Be sure that the last few unchecked joints between sub-assemblies are located where you can get to them easily if they leak. Clean the interior of the lines with solvent before assembly—this is particularly important for vacuum lines. Special cleaning pro-cedures are needed for piping in oxygen service to prevent explosion hazards. Baking may be required for lines that operate at very high vacuum. Finally, you want to pump and purge your sys-tem with clean process gas carefully be-fore you cool it down. If you cool down a system with ambient air in it, all the moisture in the air is likely to freeze at the first point that gets below 0°C and plug the line. ■

For the lowest temperatures,

vacuum jacketed piping with MLI

reflective barriers is required.

Piping System Challenges

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What development would you most like to see happen in your area of exper-tise in cryogenics and superconductivity?

We asked this question of CSA mem-bers and received an eclectic collection of replies, some very short and some lon-ger, all of which are thought-provoking and represent the variety and depth of our membership. Do any of these wishes pique your interest? Are you working on one of these issues or are you interested in contributing to the discussion? We invite responses from our readers.

Some Cryogenics WishesRichard Reineman, VP at GWR In-

struments, Inc., wishes for “a smaller, lower power 4.2K cryocooler. Anything under 500 watts input power would be great. I only need 30–50 mw of output

power at 4.2K and as-suming a two-stage system, I also need about 2 watts at 30–50K at the same time. GM or Stirling cycle look the most prom-

ising. Presently the GMs are too big for most applications and the Stirling cycle machines are only single stage and will not get down to 4.2K.” He adds, “I see endless possibilities for such a device to cool and keep cold superconducting sensors! This would expand my market 100- to 1,000-fold over what I can reach with the present1.5 Kw input systems that put out 200 mw at 4.2K and 6 w at 50K.”

Valves are the concern of Nate Paxton, TBV product manager at Cameron: “One area of development many people would like to see pertains to valves—especially as it pertains to 1/4-turn motion where there is sliding friction between the sealing components. This type of valve is speci-

fied globally for cryogenic service on many end- user specifi-cations. In the past, resilient

seats were called out (PTFE based or KEL F as examples), but now, metal seated valves are being called out more and more for cold temperature/cryogenic service.

There are reasons for this—but I won’t get into that now.

“Any time there is metal to metal contact (between the ball and the seats of the valve) for any service, most people would prefer to use some type of hard surface treatment (such as boronization) or applied coating to reduce friction and to create a better seal. Thermal swings from ambient temperatures to cold are not favorable to coatings. The repeated contraction and expansion of a coating in relation to the base metal causes it to chip and delaminate over time. So, any research into metal seated valves and engineered coatings—what works and what doesn’t—would be very desirable for the cryogenic/cold service industries.”

Our request got David-John Roth, principal of Cryoco LLC, thinking. He sent us two wishes; he thinks perhaps we could tackle them in Cold Facts. First, “I would like to see an article about mass spectro-meter leak testing using gaseous helium for various cryogenic piping components that are welded in various places.”

Roth went into detail on his second wish: “One additional topic that plagues real working cryogenic engineers [could be covered by] a concise article on vacuum gettering materials and calculations. We usually leave it up to manufacturers to use what they use. But as design engineers the subject is so diffuse and the calculations on how much of each possible getter mate-rial per vacuum jacketed item (pipe spool, field can and other custom components) are so complex that we never ever have an answer we can all agree on. I have a couple of articles, one by Glen McIntosh in an old CSA Cold Facts, that came really close. It was good but had a few gaps. I have to revisit this topic almost every four months at some place with some group.

“What we lack is: 1) A good handle on what getter materials should be used for general cryo fluids versus hydrogen and oxygen specifically.

“2) What is getter material versus con-verter (hydrogen) material.

“3) How does one calculate the nec-essary quantities of each getter/converter material based on the basic double wall stainless inner, carbon steel outer shell, construction for VJ with a basic 32 layer MLI insulation. Forget the other compli-cated struts and wire leads to make calcu-lation simple.

“4) So, how to calculate the grams of each per VJ area, a formula, a rule of thumb, something to get a handle on how much of the commercially available mate-rials to use.”

On the topic of helium refrigeration, we heard from Guy Gistau Bauger, Cryo-guy, formerly of Air Liquide. “Since I am retired (2000), I still have, as a hobby, some activity in cryogenics. As I am now provid-ing consulting and education, I am mainly dealing with users and operators of cryo-genic systems. This means that I switched from my former position of a ‘supplier’ (I was in charge of helium refrigeration at Air Liquide) to that of a ‘user.’

“In 1980, I started developing an automatic helium liquefier/refrigerator, HELIAL. At this time, the available hard-ware and software were, compared to today’s, rather primitive (limited capabili-ties as to memory size, number of control loops, calcula-tion, etc.). We had to make trade-offs but did succeed in achieving sat-isfactory oper-ation. In 2015, 35 years later, seen from my present ‘cus-tomer’ point of view, I have the feeling that the process control systems do not take advantage of the incredible progress that has been made.

Developments We Most Wish to See

smarter control systems that could inform the operator about the system status through his or her smartphone

smaller, lower power 4.2K cryocoolers

research into metal seated valves and engineered coatings

a good handle on what getter materials should be used for general cryo fluids versus hydrogen and oxygen specifically



“I would most like to see, as stan-dard equipment, smarter control sys-tems that could be really automatic, perform diagnostics, be able to take care of some imperfect settings, and inform the operator about the system status through his/her smartphone.”

A very specific wish came from Sastry Pamidi of the Center for Ad-vanced Power Systems at FSU: “A large

c a p a c i t y (300-600 W) cryocooler which goes to 10-15K that does not require p e r i o d i c m a i n t e -nance and

has high efficiency (>40%) and does not require water cooling. Many supercon-ducting applications will benefit from such a cryocooler.”

Daniel Logan, senior sales engi-neer at Janis Research Company, told us he’d like two things: “[An] ultra-miniature coaxial cable with a BeCu or SS central conductor for use from <4K to 800K. The cable could be flexible or semi-rigid, and the outer diameter should be 0.085" or less for minimal heat load. Ideally we could install our own connectors, but the option to buy the cable with BNC and SMA connec-tors installed would be good.”

Logan’s second wish: “Single in-line pin (SIP) sockets or dual inline pin (DIP) sockets that can survive up to 800K. Not the DIP chip itself—these are available already. Just the receptacle into which the DIP chip is connected.”

Citing the great future of cryogen-ics as an enabling technology, yet la-menting that it has a “low profile” and is underappreciated, John Vandore, Cryox Ltd., attributed this in part to “the lack of a ‘Standard Industry Clas-

Developments... Continued from page 25

an ultraminiature coaxial cable with a BeCu or S/S central conductor for use from <4K to 800K

sification Code’ for cryogenics—so there is less data collected compared with other sectors or technologies like electronics that do have an SIC code and so they measure those industry stats to death. Maybe one day when we grow up, we can have an SIC code, too. That’s what I’d like for Christmas!”

Neil Glasson, senior research engineer at Cal-laghan Innovation, told us, “I only wish that there were an elegant, reli-able and cheap way to safely employ solid nitro-gen as a temperature regulating buffer within a liquid nitrogen cooling system. This could be very useful for many applications of HTS where it is often desirable to regulate the temperature near the melting point of nitrogen rather than near the boiling point. Design of HTS power supply equipment in particular (cables, transformers, fault current limiters, etc.) often relies on having the liquid nitrogen sub-cooled and pressurized in order to both optimize the current carrying capacity of the superconductor and to produce satisfactory dielectric insulation performance of the liquid nitrogen.

Glasson added, “A cooling system incorpo-rating solid nitrogen could also smooth cooling demand and require smaller cryocooler capacity or allow greater flexibility of cryocooler control. There are some particularly challenging aspects of combining solid and liquid nitro-gen. Solid nitro-gen doesn’t flow well or necessar-ily stay where you might expect it to, so heat transfer and fluid flow can be difficult to predict. There is some literature describing solid nitrogen use in cooling superconducting devices, but there is much scope for further development.”

We received this wish from Moyses Kuchnir, retired from Fermilab: “I have designed and built dilution refrigerators and superfluid containers for accelerator superconducting components. But, now retired, I am a consultant on liquid N2 for my son’s dermatology clinic. I only wish that I knew about a safe chemical liquid for reactivat-ing LN2 phase separator tips. These tips are in-stalled in the end of tubes used for the transfer of liquid nitrogen from a pressurized container to a smaller unpressurized container. The N2 gas flows through and the liquid N2 drips by grav-ity in the smaller container. The porous part of the tips is made by sintering copper or brass tiny spheres. With use the surface of the tiny spheres

a safe chemical liquid for reactivating LN2

phase separator tips

a cooling system incorporating solid nitrogen


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gets a coating that eventually plugs the tip, rendering it inopera-tive. I imagine that a sealed oven with hydrogen gas in it would reactivate them, but this is not a field solution.”

Three wishes from Jacob Leachman, assistant professor, Washington State University: “1) For the CEC proceedings to have an option for submission in a peer reviewed journal, not a conference proceedings. (It’s important for us academics!) At the very least, review the proceedings and ‘award’ some submissions with full journal publication.

“2) For the national academies to release a report emphasiz-ing the importance of cryogenics to national security (similar to their recent report on the need for plasma engineers). This report needs to emphasize the importance of training engineers with cryogenic design expertise. I keep getting phone calls from com-panies and labs desperate to hire someone who’s trained and domestic, but I have no one to recommend.

“3) Small-modular hydrogen liquefaction with efficiency better than 30% of Carnot. This would kickstart the US hydrogen economy, which will almost totally rely on

cryogenics for the first two decades. This will also reaffirm the importance of cryogenics with the general public.”

Some Superconductivity Wishes“As a researcher in cryogenics, I wish people will never

discover room-temperature superconductivity. As a physicist, however, I would wish they do… As a pessimist, I would say they need to hurry because of global warming!” These are the sentiments of Marcel ter Brake, University of Twente.

Marty Nisenoff, retired from the US Naval Research Labo-ratory in Washington DC , told us, “It would be very impressive if, in 2015, a thin film integrated device technology were dem-onstrated using high temperature superconductors which could result in the fabrication of large number of Josephson junctions on a chip with very high (near 100 percent) yield and with parameter spreads of less than several percent. This would facilitate the de-velopment of a larger number of electronic applications of high temperature superconductivity, such as sensors, amplifiers and passive circuit elements and even possibly digital computing.”

Ralph Scurlock, Kryos Associates, retired from University of Southampton, asks, “What has happened to the superconducting dream? In my History and Origins of Cryogenics of 1992, I wrote a final chapter on the future of cryogenics and the many applica-tions which I predicted would grow. Most of my predictions have turned out to be correct, except one. The expected expansion of superconductivity into the electric power industry has fallen by the wayside. Why? The industrial scale of superconducting ap-plications has been established by CERN with the LHC, and now by Caderache with ITER. The experience being developed should be enabling the electric power industries to make enormous ad-vances in large energy storage systems, cryogenic power cables, fault current limiters, etc. However, my dream of 1992 is still a dream.” ■

small-modular hydrogen liquefaction with efficiency better than 30% of Carnot


Space Cryogenicsby Dr. Peter Shirron, NASA/Goddard Space Flight Center, [email protected]

When the James Webb Space Telescope (JWST) was first conceived in the mid-1990s, it

was to be as revolutionary in its cryogen-ics design as it was in the science capa-bility of its instruments. After almost 20 years, and a far larger investment than the original $500 million price tag, the flight instrument is nearing completion and the scheduled launch in 2018 appears realistic.

The JWST mission will answer funda-mental questions about the formation and evolution of galaxies, stars and planets and the re-ionization of the early universe. To do this, its four science instruments—MIRI (Mid-Infrared Instrument), NIR-Cam (Near Infrared Camera), NIRSpec (Near-Infrared Spectrometer) and FGS (Flight Guidance Sensor)—will perform both imaging and spectroscopy from the mid-infrared just into the visible band (in wavelength, from 28 microns to about 600 nm). To observe some of the oldest and most distant objects in the universe, the telescope must be able to collect light over a very large area; hence, the primary will have a diameter of 6.5 meters and a col-lecting area of more than 25 square meters.

Cryogenics is vital to JWST’s objec-tives, as it is necessary for the telescope and instruments to be cooled to below 50K in order to prevent thermal emission from the mirrors and other components from contaminating the signals from celestial sources. And while the majority of the in-struments can operate with the required resolution at about 35K, the mid-infrared instrument, MIRI, requires cooling to a much lower temperature—6K. This will be accomplished by a pulse tube/Joule-Thomson cryocooler made by Northrup-Grumman.

With a primary mirror far larger than anything previously launched, JWST fully embraced the open architecture concept in which the telescope and instruments are not contained within the vacuum envi-ronment of a dewar, but in the vacuum of space. This basic concept was success-

James Webb Space Telescope Is Becoming a Reality

JWST deployment: (1a) The fully stowed configuration, (1b) sunshield support frame deployed, (1c) unfolding and tensioning of the sunshield, (1d) fully deployed telescope. Images: JWST

1a 1b

1c 1d

fully implemented on the Spitzer Space Telescope, but JWST takes it to a whole other level.

Spitzer used both radiative cooling and a tank of superfluid helium to cool the 0.85-meter-diameter telescope, which could fit within the confines of the Delta II rocket’s fairing. On JWST, the telescope and instruments are radiatively cooled by maintaining a constant view to deep space and using a multilayer sunshield to block solar radiation. JWST’s telescope is so large, though, that the enormous sunshield needed to protect it thermally doesn’t even come close to fitting into a rocket fairing.

So how do you launch an instrument that’s as big a tennis court? You fold it up—

very carefully. You add hinges and latches and pulleys and extension mechanisms, and you fold the telescope and sunshield over on themselves until they fit into the space you have. The challenge is enormous and has never been attempted before. The sunshield alone has more than 100 pin ac-tuators holding it in place for launch, and about half that number of additional actua-tors are needed for stowing and deploying the telescope’s side mirrors, secondary mirror boom and the sunshield supports. All of this must work flawlessly in order for JWST to emerge from its cocoon after launch and reach its final configuration.

This will happen in stages during the satellite’s long journey to L2. An animation of the full deployment sequence can be


found on the JWST web site (http://2csa.us/jwst) and on YouTube (http://2csa.us/d9). At bottom left we show just the major steps, from the fully stowed configuration (1a) to extending the support frame (1b) to unfolding and tensioning the aluminized kapton layers (1c) to deploying the sec-ondary mirror and side segments of the primary (1d).

What makes JWST particularly chal-lenging is that its sheer size precludes testing many of the critical functions and assemblies in a flight-like configuration. There is no thermal vacuum facility large enough to accommodate the full instru-ment so that the sunshield and other ra-diative structures can be verified fully, and gravity effects cannot be eliminated during deployment tests. A significant ef-fort is therefore being invested in testing individual subsystems to gain confidence in their performance and to validate ther-mal models.

Recent milestones include the suc-cessful deployment test of the sunshield at Northrup-Grumman in October 2014 (see

photos, page 30) and of the secondary mir-ror boom at NASA/Goddard Space Flight Center (GSFC). Videos of the sunshield and mirror boom deployment tests can be found at http://jwst.nasa.gov/sunshield.html and http://2csa.us/da.

Preparations are underway at NASA/Johnson Space Center (JSC) for testing the mirror and instrument package. This will eventually include the flight mirrors, which have already been delivered by Ball Aerospace to GSFC, and the module con-taining the four instruments, which has also been assembled and extensively tested at GSFC. The instrument assembly will undergo vibration testing in April of this year, after which they will be retested to verify no change in performance, and sent for integration with the telescope. During this same time, the flight telescope back-plane will be delivered to GSFC, at which point the mirror segments will be installed. Integration of the instrument assembly and telescope is expected to occur in early 2016.

Full-scale telescope and instrument tests will then be conducted in Chamber

A at JSC, a 40-foot-diameter, 60-foot-tall thermal vacuum chamber with an inter-nal shroud cooled by a massive turbo-expander cooler to 10-15K, simulating the background of space. The chamber is outfitted with the Center of Curvature Op-tical Assembly, or COCOA, that is used to verify the shape of each mirror segment at cryogenic temperature.

In late 2014 the JSC chamber under-went commissioning tests to verify that the thermal environment it provides is correct. Complicating matters is that the COCOA must operate at room temperature and imposes large radiative loads when in use. Consequently, the chamber includes an MLI shutter to isolate it from the mirror as-sembly for most of the testing. Radiometers developed at GSFC that measure total radi-ative flux over a narrow field of view (about 10 degrees) are stationed around the cham-ber to measure emission from the chamber itself and that of instrument components. Using a mass simulator for the instrument, the commissioning has successfully verified



Space Cryogenics... Continued from page 29

that the chamber can achieve the temperature and vacuum conditions required for flight component testing.

The next steps are two sub-scale tests of the non-flight mirror segments and a ther-mal-mass simulator in preparation for testing of the flight telescope and instrument pack-age—in true NASA form, this assembly is called OTIS, which is a combination of the OTE (Optical Telescope Element) and the ISIM (Integrated Science Instrument Module). (On JWST, even the acronyms have acronyms!) It is expected that testing at JSC will continue through late 2017, at which point OTIS will be shipped to Northrup-Grumman in Cali-fornia to be assembled with the spacecraft bus and sunshield. Final (limited) tests of the whole observatory will precede shipping JWST to French Guiana in the late summer of 2018. Launch is planned for October 2018.

JWST will launch from an Ariane 5 rocket from Kourou, French Guiana, into a halo orbit at L2. The cruise phase lasts about one month, during which the sunshield and

telescope will be fully deployed. By then, JWST will have been a 22-year, 8 billion dol-lar investment. You can bet there will be some nervous engi-neers, scientists and managers watching as JWST begins to unfold. Hopefully they will be able to breathe a huge sigh of relief when it’s all over. ■

Sunshield deployment test: (2a) stowed sunshield, (2b) unfolded sunshield, (2c) fully tensioned sunshield. Images: JWST

2a

2b

2c


Important lessons learned from past mistakes

by John Jurns, Senior Cryogenic Engineer, European Spallation Source, [email protected]

Cryo-Oops

I have the habit of writing down notes about possible topics for this article. As I was looking though my notes this

month, I was struck by a theme that seems to come up with remarkable regularity. So what is that theme? Contamination. Of course, contamination is a problem in any engineered system, so cryogenics is not unique in that regard. However, I can say that there are some typical problems with contamination in cryogenic systems that can have particularly annoying con-sequences when they pop up.

Before I go any further, I think it is important to define what we are talking about. I picked up a dictionary and found the following definition: “Contaminate: verb (used with object). To make impure or unsuitable by contact or mixture with something unclean, bad, etc.” The point to note here is that a contaminant is some-thing that makes your system unsuitable for its intended use. That is to say, you may have something in your system that was not intended to be there, but if it does not have any negative impact on your system or process, you may not need to worry too much about it. On the other hand, we also need to understand that what constitutes a contaminant can be situational. That is, some impurity may be inconsequential in one case but detrimental in another. I’ll give an example of this later.

BackgroundThe first thing to remember is that

we live in an imperfect world. Practically, there really is no substance that does not have some impurity in it. The question to consider is to what degree or amount does an impurity exist, and if that amount of contaminant is a problem.

What constitutes a contaminant? In cryogenic systems, contaminants gener-ally consist of:

• Particulates• Oils or hydrocarbons• Trace amounts of other gases

• Moisture • Organic things (e.g., bugs)

Where can these contaminants come from? Particulates can be introduced into a system in many ways. One (very preventable) way is just from sloppy pro-cedures. An example of this could be a transfer hose that has not been properly protected from the environment. If the hose connection is not capped when not in use, dust and dirt can find their way in. Believe it or not, I have seen cryogenic transfer hoses dropped on the ground after being disconnected from a dewar without the end being capped first. Par-ticulates can also be generated internally.

Whenever you have moving parts (for ex-ample, cryogenic pumps), there is risk for something to break off and get into your system. Particles can also be generated by erosion: High velocity fluid traveling through your system can erode materials.

Oils or hydrocarbons can be intro-duced by equipment that is inherently a part of your process. An example of this is the warm compressor for a helium cryoplant. Helium compressors are com-mercial equipment that require oil to seal and lubricate rotating parts and operate properly. Oil coalescing filters are in-cluded in these systems to remove traces of oil before the helium gets to the cold box. However, failure of these filters can result in oil ending up in the cold section of the plant and freezing and plugging heat exchangers.

Trace amounts of gases are always present in cryogenic fluids due to the na-ture of how they are produced. Producers are careful to control the quality of their product and advertise the purity in their literature. However, having a leak or leav-ing a valve accidentally open in a sub-atmospheric system can result in ambient air being sucked into the system. Moisture can sneak into your system the same way. If some part of your system operates at sub-atmospheric pressure, if you suck in air you will also be sucking in any water that is in the air.

With moisture, again, transfer hoses can be a problem. Disconnecting a hose from your system before it warms up will result in moisture from the air freezing out onto your connection. Make sure the con-nection has warmed up and been cleaned and dried before you plug it in to your system again!

Organic things—you would be sur-prised what might crawl into your system. Bugs and critters generally ignore warn-ing signs when looking for a spot to make themselves comfortable. That is to say, keep your connections capped.

Figure 1: A pipe is half-filled with fine-grained powder from the adsorber. Image: STFC Daresbury Lab

Typical Cryogenic Contamination Problems

Trace amounts of gases are always

present in cryogenic fluids due to the

nature of how they are produced.


A few examplesI mentioned in the last issue that I had

attended the Cryogenic Operations work-shop at the STFC Daresbury Laboratory outside Manchester, England. One of the talks was about contamination problems they had at their ALICE (Accelerators and Lasers in Combined Experiments) facility.

The facility has a cryogenic helium system that provides 2K cooling to a few superconducting radiofrequency mod-ules. They had some performance prob-lems in 2013 that required changing out an adsorber. After they put the system back in operation, they continued to have problems and finally had to shut down the system again. They found carbon dust in some of the piping and compressor oil contaminating the cold box. The carbon was from the adsorber and the particles were small enough to escape from the ad-sorber into the downstream piping.

Typically, care has to be taken when filling the refrigerator adsorber vessels to remove any powder beforehand by siev-ing. Only pellets larger than a minimum diameter should be used. However, cool-ing down or warming up the adsorber

pellet bed may generate some powder. Apparently in this case the carbon pel-lets had broken down and produced this powder. A picture of the piping cut open is shown in Figure 1—note the pipe is half-filled with fine-grained powder from the adsorber.

I have what I think is an interesting example of trace gas contaminants in a liquid hydrogen experiment. Back in the late 1980s, we were doing some tests on Joule-Thomson (J-T) devices. We found that under certain conditions these orifices slowly plugged up. We could reset the experiment and eliminate the clogging, but we were not sure what was causing it in the first place. We had proposed that the clogging was due to trace amounts of metastable, supercooled liquid neon in the liquid hydrogen supply. The clogging took place when our liquid hydrogen was between 20.5K and 24.4K, and we noted that the triple point temperature of neon was 24.5K. I have included a chart from the original tests performed at NASA Glenn Research Center in 1988 in Fig-ure 2 above. The quality of the image is not very good, but I wanted to include a hand-drawn chart for the old-timers who

remember the time we had to use pencils and graph paper.

We looked at the purity specification for the hydrogen that we were using and found no reference to neon concentration. We contacted the hydrogen supplier, and they said that they never had any prob-lems with neon reported and did not test for it. We ran some simple calculations to determine how much neon would be required to plug up our J-T devices, and it turned out that concentrations in the parts-per-billion range were sufficient to clog them. Being clever engineers, we thought we would just buy an analyzer to measure neon concentration, but when we went to the market we found out that there was no analyzer that had the sensi-tivity to measure in the ppb range.

So you can see that an impurity that normally is totally innocuous can be a problem under the right conditions. We were not able to eliminate the neon, but we were able to come up with a number of mitigation strategies to deal with the problem.

My last example is about bugs. Many years ago, I was working with a liquid hydrogen test facility. We at one point inadvertently left a hose connection open. The 1/2"-diameter hose was connected back onto our system, but when we tried to flow through it, it was plugged. We dis-connected the hose and found it plugged with what looked like cement. A little more investigation revealed that it was just mud. Apparently, a 1/2"-diameter orifice is just about the right size to make a cozy home for mud daubers—small wasps that build their homes using dirt. Needless to say, we were then much more careful about keeping our hoses capped!

Important things to rememberFirst of all, get it clean. That is, when

putting your system together, follow proper procedures for cleaning. The Com-pressed Gas Association is a good resource for standards to clean equipment for oxy-gen and for cryogenic service. Another good reference for cleaning equipment for cryogenic oxygen service is ASTM G93-03. Your company or institute may also have its own standards that must be followed.

Figure 2 : Decrease in LH2 flow rate in a Visco-Jet J-T device. Image: NASA Glenn Research Center



Research and Development of Large-Scale Cryogenic Air Separation in Chinaby Limin Qiu, Xiaobin Zhang, Jianye Chen, and Xuejun Zhang, all from the Institute of Refrigeration and Cryogenics, Zhejiang University; Lei Yao, Hangzhou Hangyang Co. Ltd.; and Yonghua Huang, Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University

Industrial gases such as oxygen (O2), nitrogen (N2) and argon (Ar) can be re-garded as the “blood” of modern industries like the steelmaking and chemical product industries, which are the world’s primary users of the products of air separation units (ASUs). At present, the production of large quantities of high purity industrial gases still mainly depends on a large-scale cryogenic air separation method. Here, the terminology “large-scale” means that the O2 production of a single ASU is beyond 60,000 Nm3/h.

Development of China’s Cryogenic ASU Technology

At the beginning of 1953, the produc-tion capacity of an ASU was only 20 m3/h

O2 in China. After 60 years of development,

China now has the ability to produce a se-ries of commercial ASU products with a ca-pacity ranging from 20,000 to 100,000 m3/h. Since 2011, the Hanyang Group, China’s largest air separation enterprise, has been manufacturing a 120,000 m3/h ASU for Iran Carvedilol Group.

Figure 1 presents the evolution of the technology of the cryogenic air separation industry in China during the past years. In spite of its late development, China has been catching up with the pace of inter-national development through the inde-pendent innovation of ASUs since about 1986. From then on, air booster and high pressure gas expansion processes with mo-lecular sieve purification and distributed control system (DCS) were developed and

applied. The extraction rate of O2 and Ar reached 93-97% and 54-60% respectively in that period. Significant progress was made in 1996 with the application of the struc-tured packing column, which has become the most common-used facility nowadays. Compared with the traditional sieve plate column, the structured packing column has the advantages of lower operation pressure in the upper column and a higher efficiency in the production of pure Ar; thus it assists in lowering the overall power consump-tion and increases the extraction rate of O2 to 97-99% and Ar to 65-84%. Since the beginning of the 21st century, the internal compression process with liquid oxygen (LO2) pumps has begun to be widely used to replace the traditional gaseous O2 com-pressor at room temperature to increase high pressure O2 production. The internal


compression process has the advantages of flexibility, reliability and safety.

State-of-the-Art ASU in ChinaPresently, air separation processes

comprise the following basic characteris-tics: molecular sieve adsorber; structured packing column; fully distilled Ar produc-tion without hydrogen, external or internal compression of N2 and O2 products; inter-nal compression of liquid argon; and DCS control. All of the above technologies are currently being applied to China’s modern large-scale ASU with the features of high loads, multi-conditions, automation, high efficiency and reliability.

In China, the mature 60,000 Nm3/h ASU, which was produced by Hangyang for the coal-to-alkene project in the city of Baotou, can be taken as a chief example to illustrate the present technological ad-vancement of ASUs. In this unit, the struc-tured packings are used in the main upper and Ar columns, and the compressed air is efficiently cooled by an evaporative cool-ing technology without the freezer. Other technologies embedded include double bed adsorption and two floors of condenser/ evaporator. The device successfully went into operation in 2010 and is now operating to produce O2 and LO2 with purity higher than 99.6%, and O2 contents in liquid ni-trogen (LN2) less than 10 ppm. The abso-lute pressure of O2 and N2 is 8.6 MPa and ≥ 0.9 MPa, respectively, and the extraction ratios are > 99% for O2 and > 82% for Ar. Although the specific power consumption of 0.38 kWh/m3 O2 is slightly higher than the international consumption of 0.28~0.3 kWh/m3, its advantages of proprietary intellectual property and low price show great significance to the industry, as in the

past, ASUs at this level being assembled in China had to rely on imports.

Problems and ProspectsThe domestic design and manufacture

of large-scale ASU has made tremendous inroads in China, and the gap between international and domestic technologi-cal knowledge has been greatly reduced. However, comprehensive technological differences still exist compared to abroad, especially with regard to the construction of 80,000 to 100,000 m3/h ASUs. For ex-ample, China has already qualified inde-pendent design and production of static equipment and some dynamic equipment, such as large-flow air compressor units, but for other dynamic equipment—such as turbo expanders, key cryogenic valves of high pressure or large pressure difference, large-flow high pressure cryogenic liquid pumps and instrumentation—the reliance on imported equipment persists. For reli-able operation, the upper column and Ar column of the 60,000 m3/h ASU are still designed by the Swiss Sulzer company and equipped with its PLUS packing for better performance and reliability. Overall, there is still much room to improve the scientific and technological innovation capability.

Currently, new technologies in air separation equipment are still emerging, such as the large double-layer radial flow adsorber. Recently, the internal thermally coupled approach has been extensively studied, and its application to the distilla-tion column air separation process has also been proposed. Based on theoretical calcu-lations, when compared to a conventional thermal coupling column, the energy-saving effects of the new method are very


Figure 1: Technological evolution of the cryogenic air separation industry in China

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significant. These technological innova-tions are all based on a deep understanding of the basic hydrodynamic and thermody-namic theories, as well as advanced experi-mental methods. Therefore, in order to be on par with international standards, inde-pendent innovation should be encouraged. On one hand, basic theoretical and experi-mental studies, such as two-phase flow and heat and mass transfer in complex structures, need to be further strengthened. On the other hand, enterprises should ac-tively change their management concept to become suppliers of both facility and gas, rather than only device providers. This will lay the foundation for applications of new technologies, because as gas suppliers, the risk of damaged reputations and commer-cial disputes from setbacks or failures can be minimized.

After more than two decades, and es-pecially in the last decade or so, through independent research, technology intro-duction, co-production and the improve-

ment of old equipment and operating practices of over 10 sets of large-scale ASUs, Chinese enterprises have successfully resolved a large number of key technical equipment design and manufacturing is-sues. These technologies primarily include process design to meet needs, equipment design with specified performance, and so on. China is now able to independently manufacture 60,000 Nm3/h ASUs and has the capabilities to design and manufacture larger ASU systems up to 120,000 m3/h. Among these, most static equipment can be designed and made in China, while some special devices, such as large-flow expanders, high pressure cryogenic liquid pumps and cryogenic valves, generally have to be imported. From the perspective of cost, this combination is currently con-sidered to be an optimal solution—namely,ensuring that the device is advanced and reliable with a lower investment and op-erating cost. Specifically, as the device-supporting enterprise, Shaangu Power Company Ltd. has the ability to inde-

pendently design and manufacture air compressor units for 120,000 Nm3/h air separation system after accumulating suf-ficient research development and technol-ogy over the years. It also provides system solutions and services for units in the air separation industry.

In general, power consumption ap-proaches 0.38 kW/m3 O2 with the domes-tic large-scale 60,000 m3/h ASU, which features long-term safety, reliable and easy operation and good appearance. Thanks to technological advances, Chinese air sepa-ration firms not only account for more do-mestic market share, but also show greatly enhanced international competitiveness. For example, Sichuan Air Separate Group, one of the four air separation enterprises in China, exported a 10,000 Nm3/h ASU to Turkey; Hangyang exported a 20,000 Nm3/h ASU to Spain; and a 120,000 Nm3/h ASU was exported to Iran in 2014, which is the largest ASU exported by China by far. ■

Air Separation in China... Continued from page 35


Featuring Women in Cryogenics and Superconductivity

Several years ago Cold Facts had a cover story on women in cryogenics and superconductivity. It elicited some surpris-ing and interesting responses. We thought it was time to introduce our readers to several more women who are excelling in our fields and find out more about their experiences in areas where they are still pretty much in the minority. We sent them several questions that they could answer. Each answered in her own unique way.

Questions:• Who were or are your mentors? Are any

of them women? Do you have the same support and mentoring as men in your field?

• What challenges and/or advantages have you experienced as a woman work-ing in a STEM field?

• Are you assertive in the workplace? How do your colleagues respond—posi-tive or negative reactions?

• Do you see a noticeable difference be-tween how colleagues interact with you and how they interact with male col-leagues?

• What advice do you have for women in STEM careers who are coming up now and in the future?

Marianne BossertMechanical Technician, Fermi National Accelerator Laboratory. Per-forms mechani-cal assembly and testing of superconducting magnets and their many com-ponents

I’ve been very lucky to have excellent mentors throughout my career. Emanuela Barzi has always guided me in our research and has provided endless direction in han-dling the difficult situations that arise as a result of being a woman in a STEM field. Watching the way she has handled these experiences herself over the years has been an inspiration to me, and I can’t thank her enough for all she has taught me.

Tom Van Raes has also been an in-credible technical mentor. When I started

working at Fermilab, I had research experi-ence, but limited technical experience. Tom taught me everything he knew, from the very basic to the complex, and was always patient when I had questions.

The most striking characteristic I’ve no-ticed in the way my coworkers act toward me is that they frequently assume I’m inex-perienced until, and sometimes even after, they learn otherwise. As a result, coworkers are eager to help me out when I am new to a role. The challenge is that they can be slow to recognize when I have grown and developed in that role and subsequently have ideas based on that experience that could benefit them.

I have oscillated between meekness and unapologetic self-assuredness, which has resulted in being overlooked as a con-tributor and being looked at as pushy, re-spectively. I would like to think I’ve now settled on a middle ground; I’ve learned to be observant enough to identify work-re-lated problems just as they begin, and put a stop to them in a firm but unobtrusive way.

I feel that I am expected to constantly prove my skill as a technician while the males’ skills are assumed. The most no-table experience illustrating this concept occurred during a technical discussion be-tween a male technician, two engineers and me. I was experienced with the topic being discussed and chimed in with two sugges-tions. My contributions were overlooked, but later in the discussion the male techni-cian, who had no experience in these tech-niques, made the same suggestions and the engineers listened and incorporated them. I was amazed at the time, but similar situa-tions continue to occur regularly.

The most constructive reactions to sexism at work in my case have been first acknowledging that it occurs, and then understanding that it is unintentional. The engineers in the earlier story did not inten-tionally ignore my comments—they likely didn’t understand or consider them. Be-cause I understood that the behavior wasn’t malicious, I was able to make changes to my level of assertiveness that resulted in im-provements in the situation. Assuming the other party is malevolent is the first step to creating a situation in which both sides are defensive and nothing will be solved. When we recognize these problems, the intentions behind them, and their fallout, we can take

non-confrontational corrective actions to ensure our voices are heard.

Haixia XiLead Mechanical Design Engineer-Cryogenic, General Electric Health Care, MR magnet cryogenic system design

No special men-tor for me, but I can ask any technical questions to any of my colleagues and

they will help me with patience, just as with their male colleagues. Currently my main support is from male colleagues, because there are few women in the cryogenic and superconductivity field.

Like other female engineers, my main challenges are maintaining balance between family and work. However, we do have the advantage of communicating easily with colleagues as female engineers.

I just joined the Florence South Caro-lina team in the past four months and still am learning a lot of new stuff. When I have built the capability, I think I will be assertive in the workplace. At GE, if you maintain a positive manner, your colleagues will al-ways respond positively.

I don’t see a noticeable difference be-tween how colleagues interact with me and how they interact with male colleagues.

I would advise women in our field to stay curious: you can find a lot of fun in STEM!

Beth EvansSample Environ-ment Project Manager and Chair of the British Cryogenics Coun-cil, ISIS Neutron Facility, Rutherford Appleton Labora-tory. Evans man-ages, and provides design input to, projects to provide cryogenic equip-

ment for use on neutron beamlines and other technological projects for ISIS, but she has also managed inter-facility sample environ-


Dr. Xiaoqin Zhi, who graduated from the cryogenic group Cryoboat of Zhejiang University in China under the direction of Professor Dr. Limin Qiu, now works as an associate researcher at the University of Wisconsin-Madison (UW-Madison) with Professor John M. Pfotenhauer, continuing her research in the US cryogenic commu-nity. In the following year and a half at UW-Madison, she will conduct a combination of modeling and experimental work address-ing heat transfer, fluid dynamics and cool-ing system design for a variety of cryogenic applications including cryocoolers, air sepa-ration and superconducting magnets.

During her doctoral study, Zhi car-ried out research on the multi-stage Stirling pulse tube cryocooler (SPTC). Through her cooperative research at the University of Giessen with Professor G. Thummes she was able to achieve minimum temperatures of 4.26K with He-4 as the working fluid, and 4.03K with He-3 as the working fluid in a three-stage SPTC. These results represent a world-record accomplishment for multi-stage SPTCs, and are inspiring for the vari-ous groups working in cryogenics, including the aerospace corporations who are leading the development of such coolers. Zhi also demonstrated a deep understanding of the detailed thermodynamic cycles occurring within the pulse tube cryocooler, thereby illustrating a new working mechanism of the pulse tube cryocooler from a microscale

perspective. Professor Pfotenhauer com-menting on this work remarked, “For all of us exploring the thermodynamics and heat transfer within these deceptively simple-looking refrigerators, it is a great pleasure when a colleague unlocks some new under-standing of their performance, or surprises the community with a novel approach that improves their cooling capacity.”

Zhi has recently been selected as the winner of the Carl von Linde IIR Young Researchers Award by the committee of In-ternational Institute of Refrigeration, for her outstanding work in cryogenic engineering. The committee was pleased to recognize her high quality contributions to the field of cryogenics, especially as one of the few female researchers in this area.

“Cold and hot are the most basic feel-ings in nature, which makes the cryocooler and heat transfer study very intuitive and vivid to me. I am not just choosing cryogen-ics as a career; I do love it. Besides, cryo-genic technology is an essential supporting technology in many areas, and I feel a great sense of accomplishment when doing my research well,” said Zhi. “There are some difficulties for women to work in an engi-neering field like cryogenics, but I believe that my feminine characteristics of careful-ness, meticulousness, patience and even assertiveness help me to do my research well. Furthermore, an increasing number of

opportunities are being provided to help women advance their careers within the worldwide cryogenic community, and it is becoming easier for women to study and work in cryogenic engineering. As in my own case, it has been very helpful and en-joyable to work with leading experts world-wide from Hangzhou, to Giessen, and to UW-Madison. I feel women are welcomed in the field of cryogenic engineering. We receive the same support from our cowork-ers and mentors as do our male colleagues. Sometimes, we are even more likely to win recognition and admiration when doing a good job, especially in China. So, I encour-age females who are interested in this field to confidently jump in and believe you can do it well through hard work.

“Women can work independently in the field of engineering. They can work as well as, or sometimes better than, men. ...We hope more talented women will choose to work on cryogenics to make this field more lively.”

“Women, Work Independently and Preeminently on Cryogenic Engineering”by Dr. Xiaoqin Zhi, associate researcher, University of Wisconsin-Madison, [email protected]

ment projects and the organization of work-shops, training schools and public engagement events.

I have not had an official mentor, al-though I have been given the opportunity to manage some very interesting projects by the ISIS deputy director Zoë Bowden, and through these, and her guidance, I have learned a great deal.

The greatest challenge I have experi-enced as a woman working in a STEM field has been balancing work and home life. Having a family and changing to part-time hours in an environment where I was the first to have done so means that perhaps I

have experienced less understanding of my reduced flexibility in terms of travel and availability.

I am sure many women working in a STEM field can recall a host of “inappropri-ate” comments made by male colleagues, mostly in jest, and/or the feeling of isolation when faced with the prospect of being the only female at a meeting, or even at an en-tire conference. But this also has the distinct advantage of becoming instantly memora-ble to potentially useful contacts. My advice to women in a STEM career who are coming up now and in the future is to work hard, be yourselves and keep your senses of humor.

Pascale DauguetScientific Market Manager, Air LiquideAdvanced Technologies (AL-aT). In charge of marketing and sales of cryoplants (helium

refrigerators and liquefiers, turbo-expanders and cryogenic compres-sors, valve boxes and cryogenic transfer lines) in Europe and the Americas, for scientific labs and helium gas fields (helium extraction units)



My mentors were Louis Burnod (CERN), Jacques Chaussy (CNRS) and Guy Gistau (AL-aT). None of them were women. I have benefitted from the same level of support and mentoring as men in my field. Twenty years ago, beyond your diplomas, references and professional po-sition, half the time during the first meet-ing with a new interlocutor, as a woman you had to strongly demonstrate that you were the relevant person for the job. I was more challenged than my male colleagues. But after demonstration of your abilities, the fact that you were a woman turned out to be an advantage, with the negative “a-prori” turning to positive respect, even admiration, especially in countries were the employment rate of women was low.

I feel that this “special treatment” is less the case today. Nowadays the behav-ior of professional interlocutors in STEM is more neutral regarding the sex of the pro-fessional they are working with, which is a good improvement, certainly due to the increased number of women in STEM fields in the last two decades. I do not see a no-ticeable difference between how colleagues interact with me and how they interact with male colleagues.

I would advise younger women to con-sider that a STEM career is nowadays fully compatible with a balanced family life and with children’s education, for both men and women. The job can be shared. And this is a good example for your girls to follow. Be confident, demonstrate your talents to oth-ers, express your professional expectations and ask for promotion.

Iole FalorioResearch Fellow, University of Southampton, Characteriza-tion of HTS superconduc-tors in critical conditions, in a wide range of temperatures and fields. Falorio’s job includes the design of the sample holder required for

the specific measurements, the manufacturing of the mechanical components required for

measuring, the sample test, the post-processing and the analysis of data.

My mentors are Professor Yifeng Yang, Dr. Edward A. Young and Professor Carlo Beduz. My research group (including pro-fessors, lecturers, research fellows, PhD students and technicians) is composed of 10 people and only two of us are women. I have been working in this research group for four years now and I consider my work-ing experience very positive. The people in my working environment are very open-minded and as a consequence I have never felt any kind of difference in treatment be-tween me and my male colleagues.

The main challenge I’ve had to face when I started working in superconductiv-ity and cryogenics was to work in a mechan-ical laboratory, which requires very strong practical skills. Although my parents cer-tainly did their best for my education, I was never encouraged or involved during my childhood in solving practical problems—it was done instead with my brother, since this was considered to be more a man’s job. Also, my background at university was more theoretical than practical; therefore, I felt very unconfident when I first started to face experiment setup problems and the need to design, manufacture and assemble mechanical components. Curiosity and ob-servation have been, and still are, my tactics for stepping forward and overcoming these limitations.

Communication is very important in my research group and all opinions are welcome for discussion among the team. So in general terms my colleagues respond in a positive way and I don’t see any noticeable

difference in treatment between me and my male colleagues.

I think that dedication and enthusiasm for the work are the keys to being respected and treated as a professional in any work environment. Feeling such a respect from others is essential to gain self-confidence and makes it easier not only to express yourself in work discussions but also to build more personal relationships with your colleagues. Also, as a woman in science, I have never tried to hide my feminine side and I do not think that hiding it or follow-ing any stereotype would help a woman to be given more consideration; my personal objective is to keep on growing profession-ally and humanly, showing who I really am.

Agnieszka PiotrowskaDoctor Engi-neer, Wroclaw (Poland) University of Technology

My choice of technical studies was not a coinci-dence. Prob-lems requiring a mathematical

background and logical explanation were always much easier to understand and solve for me than learning by heart. At the beginning I wanted to focus on refrigera-tion technologies, but after the first lecture on cryogenics I was sure about my future profession. Therefore, I decided to continue my education as a doctoral student in cryo-genics technologies at Wroclaw Univer-sity of Technology. My PhD studies were dedicated to thermodynamic optimization analysis of an autonomous system for liquid nitrogen production in small quantities. The concept was based on coupling N2 separa-tion technology (polymer membrane) with a Joule-Thomson cryogenic cooler.

Currently I hold the position of assistant professor in the Department of Cryogenics, Aeronautical and Process Engineering at Wroclaw University of Technology. I’m a lecturer and supervisor of both engineers’ and masters’ theses and cryogenic technolo-gies projects. Three years ago I joined the teaching staff of English-language Master Studies in Refrigeration and Cryogenics.

Women in Cryogenics... Continued from page 39

Young women coming up in the

field should never fear or have any

doubts about working with men.


Besides my duties as an academic teacher, I’m involved with the Strategic Pro-gram Advanced Technologies for Energy Generation: oxy-combustion technology for PC and FBC boilers with CO2 capture sup-ported by the National Center for Research and Development. As a project engineer I’m involved in the development of medium ca-pacity cryogenic coolers. My research pro-gram is focused on Joule-Thomson coolers working in a closed system and supplied with gas mixtures. I’m also interested in risk analysis of cryogenic systems. My interest in quantitative risk assessment methodol-ogy is influenced by the fact that cryogenic industrial installations and scientific facili-ties become more and more complex and require an increasing amount of cryogens. This trend has to be followed by solutions repairing the results of potential failures. Therefore, methods for identifying hazards and for classifying failure consequences must be evolved now.

I acquired industrial experience during internships at CERN and KrioSystem (Wro-claw, Poland). I had the chance to partici-pate in the reception tests of the cryogenic

distribution line for the Large Hadron Col-lider (LHC). I spent five months at CERN working in the cryogenic group (technol-ogy department). I was also involved in the collaboration between CERN and Wroclaw University of Technology. I took part in the update of the Preliminary Risk Analysis of the LHC cryogenic system and the analysis of helium release from the helium ring line. I’m also a co-organizer and lecturer at the European Course of Cryogenics (reported in Cold Facts each year).

Public presentation is a challenge. In general, public presentations are very stressful situations. From my experience, explaining a technical problem and its solu-tion to 200 or 300 men makes me double- or even square-stressed. On one hand I must be aware that even a small mistake will be noticed, but at the same time it’s the best motivation to pay special attention to each possible detail.

There is a bright side to being a woman working in a man’s world. In a group full of men, a woman always is noticed and remembered. This results in our being rec-

ognized in the work environment from the very beginning.

I am assertive in the workplace, because my time is very precious to me. The secret is to do it in a polite but firm (strict) way. My colleagues were surprised, but they got used to it very fast. I’ve never had to face any negative reaction from them. Maybe I’m lucky, but I don’t see much difference in how my colleagues interact with me and with my male colleagues.

Young women coming up in the field should never fear or have any doubts about working with men. Although technical studies are not easy, they are definitely most interesting and give us the opportunity to use our imagination and creativity. The start-up of a system that was just a drawing at first or the opportunity to participate in big projects gives lots of satisfaction. If I had to make the choice again, I would choose Technical University once more. More-over, I’m sure that the taste of success for a woman working in a predominantly male-dominated profession is much sweeter. ■


Product ShowcaseIn the interest of enhancing the value of Cold Facts and helping prospective customers find cryogenic products and services, we’ve added this new Product Showcase to the magazine for all issues of 2015. We invite companies to send us short releases (250 words or fewer) with high resolution JPEGs of their new products.

GerhartSafeHose-PT

The SafeHose-PT prevents ac-cidental opening of an automatic valve. A special sensor detects whether the hose is pressurized. The actual pressure and status of switch (open or closed) is indicated on the SafeHose-PT. It works with AC or DC valves and includes a piping kit to tie into most existing filling systems. The SafeHose-PT is for cryogenic liquid or high pres-sure gas (up to 6000 psig) applica-tions. www.gerhart.com

Advanced Research SystemsHigh cooling power cryocoolers

Advanced Research Systems, Inc. (CSA CSM), has added three new models to its prod-uct line of high cooling power, closed-cycle cryocoolers for 4K environments. These pneu-matically driven Gifford-McMahon (GM) type cryocoolers are lighter in weight compared to mechanical drive GM cryocoolers. They also feature smallest-in-class power consumption (< 7 kW) during steady-state operation.

These new cryocoolers offer a wide range of benefits. An axial symmetric design limits off-axis vibration, making these cryocoolers ideal for applications and environments that require ultralow vibrations, such as medical imaging and nanoscale science. These cold heads can be oriented tip-up, tip-down or horizontally, so you have more options when fitting them into tight spaces. Maintenance procedures on pneumati-cally driven cold heads like these are simple and easy to follow. That means you can spend less time on maintenance and more time running your applications.

Advanced Research Systems customers have already put these en-hanced, high power cryocoolers to work in low temperature laboratory experimentation, hard-drive manufacturing and testing, cryogen-free cooling of superconducting magnets and other applications. These cold heads are especially well suited for magnetic resonance imaging (MRI). When combined with one of the company’s universal flange configura-tions, they can easily be used as a drop-in replacement in an existing MRI system. www.arscryo.com

Atlas TechnologiesRobust bimetallic transition couplings

Standard sized Al to SS bimetal transitions allow aluminum tube or pipe to be welded directly to SS tube or pipe. Used in thousands of cryogenic, ultrahigh vacuum, and industrial applications for decades.

Transition couplings handle cryogenic tempera-ture cycling and resulting mechanical deformations. At cryogenic LN2 and liquid He temperatures, the Coefficient of Thermal Expansion between interlay-ers SS (9.4), Cu (9.8), Ti (5.5) Al (13.2) and Al (13.2) acts as dampening spring, giving cryogenic compo-nents a robust resilience for repeated cycling of the bond to temperatures to –196°C and lower.

Interlayers are also very robust chemically, and proper welding procedures keep the layers insulated from intermetallic chemical reactions occurring dur-ing weld-up. The materials are rated at 300°C.

Because the interlayers between the primary metals, stainless steel and aluminum, are very thin Cu (0.03", 0.76mm), Ti (0.012", 0.3mm), Al (0.04", 1.0mm) the strength of the interface is greater than the strength of constituent metals. Average shear strength of this interface has been tested to 11,000 PSI. The bonds will withstand an internal pressure of well beyond 10 Bar.

The all-welded bimetallic joints enable cryogen, liquid or gas supply lines to transition from one metal to another: liquid nitrogen, hydrogen, helium and many other industrial gases and liquids. After TIG, MIG, or electron beam welding to standard tube or pipe, they provide a fully hermetic solution.

All Atlas bonded material is helium leak-checked to better than 1 x 10-9 Std. Torr He Lt/sec. www.atlasuhv.com


Advanced Piping ProductsCryoTek pipe shoe

Advanced Piping Products’ (CSA CSM) Cryo Tek pipe shoe is a cutting edge, non-metallic pipe support solu-tion for extreme temperature conditions. It is ideal for cryogenic piping systems that involve gas liquefaction, LNG ter-minals/carriers, ethylene plants or any cryogenic process piping. Although the CryoTek pipe shoe was originally devel-oped for use in cryogenic conditions, it also offers unparalleled performance in temperatures up to 400°F and is the pre-mier solution for cryogenic or elevated piping systems.

The pipe shoe consists of a mono-lithic unit molded from continuous strand glass mat in a hybrid thermoset-ting resin around a core of foam insula-tion. The pipe shoe boasts a compressive strength of 27,500 psi. In addition to its high strength, the composite material has a low thermal conductivity that

prevents heat sinks and fluctuations in pipe system temperatures. The resin is corrosion and UV resistant and, upon request, can be combined with an intu-mescent coating to resist temperatures up to 2,000°F, for up to two hours.

The CryoTek pipe shoe also offers many installation benefits. Installation takes a fraction of the time that it takes to install traditional pre-insulated me-tallic supports. Because it is lightweight, it can be installed without the use of heavy-lift equipment. This product re-liably succeeds in harsh applications where other pipe shoes fail, making it an exceptional pipe support for extreme temperature conditions. www.appinc.co

Fabrum SolutionsPT330W cryocoolers

Fabrum Solutions in conjunction with Callaghan Innovation have had exceptional results with their com-mercially available 330W cryocoolers. The cryocoolers have been in labora-tory tests since mid-2014, and in recent commercial applications are replicating the laboratory results. The PT330W is developing up to 415W at 77K, but in commercial format it is delivering 350W at 77K. The cryocooler uses the patented pressure wave genera-tor (PWG) and an in-line pulse tube.

The cryocoolers are ideally suited to industrial and com-mercial applications due to the benefits of the PWG. The rugged industrial motor is cost effective, robust and reliable, tolerant of poor power quality, flexible for multiple voltages and simple

to use. It also has a long life and lasts 40,000 hours between major overhauls.

The long-life metal diaphragms keep oil separate from the clean gas circuit. With no moving seals and the diaphragms acting as the flexure bear-ings, ultimate reliability and long life is ensured. The opposing diaphragm gas spring balances average pressure and provides a convenient reservoir for pulse tubes. A simple drive mechanism utilizes conventional lubrication oper-ating at atmospheric pressure requiring

no pressure control. It is easily accessible for preventative mainte-nance (oil changes) without disturbing the clean gas circuit.

The same technol-ogy is employed in the PT1000W cryocooler that is in final endur-ance testing now, with early performance indications of 1.2kw at 77K. www.fabrum.co.nz

attocubeattoDRY800 cryo-opticaltable

Quantum optics experiments often require cryogenic temperatures combined with optical access. Most experimental setups contain numerous optical elements delicately arranged on an optical table to shape and prepare the incident light, as well as to efficiently collect and convert the emitted light from the sample. The available space on the optical table is in such cases paramount to many complex setups.

The attoDRY800 consists of an ul-tralow vibration cold breadboard plat-form extensively integrated into an optical table, making use of the space underneath it. This unique design ensures unob-structed optical access to the cold sample from all directions on the optical table via one top and four side optical windows. Apochromatic objectives with high nu-merical aperture (NA=0.81-0.95) can either be integrated into the cryostat, into the vacuum shroud, or put in close working distance next to the optical windows from the outside. This ensures extremely low drifts and optimal collection efficiency.

The closed-cycle attoDRY800 requires no liquid cryogens, thus minimizing run-ning costs. In addition, a fully automated temperature control between 4 and 350K conveniently enables unattended long measurement cycles.

While many off-the-shelf closed-cycle cryostats suffer from severe vibra-tions at the sample location, special care was taken during the development of theattoDRY800 to keep the displacements to a maximum of 1 nm (RMS) by a special patented vibration isolation technology. Hence, even extremely sensitive measure-ments are possible. The attoDRY800’s cold breadboard sample space can host several of attocube’s patented nanopositioners, as well as complete microscope or photonic probe station solutions. www.attocube.com


Lauren Biron in symmetry magazine reports that scientists are joining together in an online video campaign aimed at en-couraging Japan to host the world’s next big particle accelerator, the proposed Inter-national Linear Collider (ILC).

The ILC plans to further study the Higgs boson and other aspects of particle physics. Its construction will likely take the better part of a decade, potentially cost bil-lions of dollars and require a high level of commitment and planning by the host na-tion. Asian, European and US plans for the future of particle physics all include some level of participation in a future linear col-lider.

Japan is the top candidate for siting the ILC. The Japanese high energy physics community has recommended the ILC be built on a site in the Kitakami mountains of the Iwate and Miyagi prefectures. A panel set up by Japan’s Ministry of Education, Sports, Science and Technology (MEXT) is presently reviewing the proposed hosting of the ILC in Japan.

Demonstrating their support for the ILC, scientists from around the world are posting to YouTube as part of the #mylin-earcollider video campaign.

“I think it helps politicians and bu-reaucrats and some of the people who don’t have a scientific background un-derstand that there is a lot of community support behind this,” says Katie Malone, an ATLAS researcher at SLAC laboratory who participated. “We’re really excited about it, and it’s worth the investment that they are considering.”

More than 620 videos by scientists worldwide have been uploaded to You-Tube with the #mylinearcollider hashtag since the campaign started in October 2014. Supporters filmed their responses from various locations—lab control rooms, poster sessions, lush gardens and busy

streets. Students, postdocs, fellows and professors all are shown in support of ILC.

The 19-mile linear collider would smash electrons into positrons at an energy of 500 billion electronvolts, in contrast to the 17-mile circular Large Hadron Collider at CERN, which will soon collide protons at an energy of 13 trillion electronvolts. Using elementary particles, the ILC would produce simpler, cleaner collisions and allow scientists to study the Higgs and other phenomena with increased precision.

MEXT is expected to report on ILC by March 2016, according to ILC communica-tor Rika Takahashi. But the YouTube cam-paign, which she calls a “visual petition,” won’t necessarily end with approval of the project.

“We also need to reach industry and the local people who are in the area where the ILC might be built,” Takahashi says. “This facility will be for the younger gener-ation. Many of us will be retired when the ILC starts running, so we need to reach out to the younger students and researchers.”

Many videos have come from Japa-nese scientists as well as from scientists affiliated with CERN or with institutions in Germany, the United States, Italy and India. Scientists have also posted support from Indonesia, Pakistan, Iran, Mexico, Slovenia and Serbia—truly across the globe.

Videos usually are short testimoni-als citing why the supporter would like the ILC to be built and what they hope it will accomplish. Some are simple images of the scientist with the words “I want the ILC”; others are more complex. More than a dozen scientists at the Instituto de Física Corpuscular in Valencia, Spain, present a tour of their campus while they explain why they want the new collider. Andone supportive professor plays an ILC song on the guitar, accompanied by a grad student. ■

YouTube Campaign Supports #mylinearcollider

Top to bottom: Nigel Lockyer, director of Fermilab; Heather Logan, a physicist at Carleton University, Canada; Mattia Checchin, a PhD student at the Illinois Institute of Technology, studying at Fermilab; Maria Krawczyk, a physicist at University of Warsaw, Poland; Robert Kieffer, CERN, Switzerland; and Nodaka Yamanaka, a physicist at RIKEN, Japan. Images: ILCcommunication on YouTube.

For more videos, visit https://www.youtube.com/user/ILCcommunication, or search for #mylinearcollider on YouTube.


Sunday, June 28, 2015, at the MarriottStarr Pass Resort in Tucson, Arizona

at CEC/ICMC

Register Now for CSA’s

Short Courses

Early:

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Half-Day Course

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Both Half-Day Courses

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Dr. Ray Radebaugh Dr. Ron Ross Dr. Rong-Li Geng Dr. Scott Courts

Cryocooler Fundamentals and

Space Applications8:00 am-5:00 pm

by Drs. Ray Radebaugh, ret. NIST

Boulder, and Ron Ross, ret. Jet Propul-

sion Laboratory

Superconducting Radio

Frequency Systems8:00 am-12:00 pm

by Dr. Rong-Li Geng, Thomas Jeffer-

son National Accelerator Facility

Practical Thermometry and

Instrumentation1:00 pm-5:00 pm

by Dr. Scott Courts, Lake Shore

Cryotronics

Deadline for early registration is May 15.

For instructor bios, online registration and more information about the courses, visit

http://2csa.us/sc15.

Cryo-Oops... Continued from page 33

When you specify how to clean your system, take some time to deter-mine what level of cleanliness you need. That is, for example, think about what level of particulates you can tolerate, or how pure your cryogenic fluid needs to be. You need to make your system clean enough, but specify a cleanliness level consistent with your requirements. Don’t put in a five micron filter if a 100 micron filter is sufficient for your pur-poses.

Secondly, keep it clean. Install fil-ters in appropriate places to prevent particles from migrating through your system. When commissioning a new system, check these filters often—no matter how careful you are when fab-ricating a system, a few surprises could still show up in these filters after you start up. Bits of Teflon tape, welders’ wire brushes, rocks, etc. may show up.

Monitor these filters regularly and ser-vice when appropriate.

Besides monitoring the pressure drop across filters, if required, install gas analyzers to monitor the purity of your fluid. Impurities are good indicators of leaks into your system.

Another aspect of monitoring is just watching and listening. If some equip-ment sounds noisier than usual, or seems to be vibrating a lot, that could mean something has shaken loose and is rattling around in your system.

Finally, probably the most effec-tive way to prevent contamination is to practice good housekeeping. Cap off open connections. Keep the environ-ment clear of dust and dirt that can find its way into your system. Keep good re-cords on maintenance items like filters. Inspect gaskets and replace them if they

look worn. It might not be extremely so-phisticated, but good housekeeping and vigilance are probably your best protec-tion against contamination.

In summaryIf you are careful to (1) determine

how clean your system needs to be, (2) understand where contaminants can come from, (3) design your system to minimize the possibility of contamina-tion and (4) practice good housekeep-ing, you should be able to avoid getting that phone call in the middle of the night telling you the system is down, and you need to get out of your warm bed to fix it.

As always, we invite you to share any of your “oops” stories with us. Feel free to send them in to Kelsey Beachum at [email protected], and we’lltry to include them in this column. ■


People, Companies in CryogenicsScientists

will celebrate the 20th an-niversary of the top quark d i s c o v e r y at Fermilab (CSA CSM) at

a workshop to be held from April 9-10. Fermilab announced the discovery of the top quark, the heaviest subatomic par-ticle ever observed, in 1995.

HEPTech, together with CNRS, CEA, Grenoble University, Lanef and ILL, in close partnership with CERN, the University of Twente and the Ruth-erford Appleton Laboratory, is organiz-ing a cryogenics event bringing together academia and industry, to be held in Grenoble at the CCI (“Chambre de Com-merce et d’Industrie de Grenoble”), June 4-5. The group states, “Cryogenics has

widely contributed to the recent major successes of high energy physics (HEP). And conversely, HEP has pushed cryo-genic engineering developments to a high level of technical excellence.” HEP-Tech is a pan-European HEP network created by initiative of CERN with 22 members in 17 countries.

We regret to report the death on March 16 of CSA Fellow Dr. Thomas M. Flynn. Flynn died in his sleep at home where he was in hospice care. CSA in-vites colleagues to submit tributes to be published in Cold Facts Volume 31 Number 3. Send your comments to [email protected] by April 17.

The Sponsoring Consortium for Open Access Publishing in Particle Physics (SCOAP3) started its second year of operation and celebrates the pub-lication of the first 5,000 articles. More

than 18,000 scientists from 86 countries have benefited from this Open Access initiative, publishing articles at no direct costs.

On Sunday, April 5, the world’s most powerful particle accelerator began its second act. After two years of upgrades and repairs, proton beams once again circulated around the Large Hadron Collider (LHC), located at the CERN laboratory near Geneva, Switzer-land.

With the collider back in action, the more than 1,700 US scientists who work on LHC experiments are prepared to join thousands of their international colleagues to study the highest-energy particle collisions ever achieved in the laboratory. These collisions—hundreds of millions of them every second—will


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lead scientists to new and unexplored realms of physics and could yield ex-traordinary insights into the nature of the physical universe. During the LHC’s second run, particles will collide at a staggering 13 teraelectronvolts, which is 60 percent higher than any accelerator has achiveved before.

In March, Fermilab (CSA CSM) Deputy Director and Chief Research Officer Dr. David Lykken announced the launch lab’s Women’s Initiative, a program that will sponsor events aimed at educating all employees about the ways in which women affect the work-place and the importance of promoting gender equality. The kickoff featured writer Hannah Bloch discussing global women’s issues.

Lykken said, “We hope and expect the series of events, which highlights a variety of perspectives, to cause some reflection and generate conversation

and action that has a positive impact on the culture of our laboratory. Although organized by women, it is critical that men are part of the conversation.” He also noted that March, Women’s History Month, was “a good time to reflect on the outstanding achievements of women in science, overcoming not just the usual challenges of deciphering the universe but also a professional landscape littered with gender-based obstacles.”

NASA’s Glenn Research Center in Cleveland is celebrating the launch of the Hubble Space Telescope 25 years ago this April with a series of activities for children and adults to learn more about Hubble’s amazing contributions over the last quarter century. The cel-ebration kicked off on April 1 with a Hubble@25 awards ceremony honoring Glenn’s Hubble Space Telescope team who contributed to its mission, featuring remarks by Center Director Jim Free and Aerospace Engineer Bruce Banks, who

served as chief of the Electro-Physics Branch and managed Glenn’s Hubble team.

Ann Carroll has been promoted to Sales Support, Marketing & Lo-gistics Group Su-pervisor at Janis Research Com-pany (CSA CSM). She will supervise

support staff for sales engineers and logistics/shipping and will continue to handle marketing for the company.

CSA member George Zimmerman at Boston University has brought to our at-tention the passing of several colleagues who worked in low temperatures. We are sorry to report this loss. They are Robert Meservey, who retired from MIT in the last two years; Myron Strongin, who passed away last fall and whose

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memorial was held on January 31, 2015, at Brookhaven National Laboratory; and James Brooks, who last worked at the National High Magnetic Field Labora-tory in Tallahassee FL and was a profes-sor at Florida State University.

The High Energy Particle Physics Group at the University of Notre Dame is hosting a public video contest called “Rock the LHC,” from March 23 to May 31. Participants are invited to create short videos about why they are inter-ested in the research at the Large Hadron Collider (LHC). The goal of the video contest is to celebrate particle physics and the US contributions to the LHC. http://2csa.us/d8

Daniel Dender is now acquisition specialist and contracting officer repre-sentative at NIST’s Material Measure-ment Laboratory.

The new Stargazer Lottie doll, set to be released in March, was designed in collaboration with the European Space Agency and a working astrophysicist. She has her own telescope, solar system trading cards and profiles of famous fe-male astronomers. Credit: Tariq Malik/www.space.com

Astrophysicist Neil DeGrasse Tyson is quoted by Jessica Orwig in businessinsider.com as saying this is the funniest

science joke he’s heard: “A Higgs boson walks into a church, and the priest says, ‘I’m sorry we don’t allow Higgs bosons to come to churches.’ And [the Higgs] says, ‘But without me, you can’t have mass.’” DeGrasse Tyson says he first heard this joke told by science comedian Brian Malow.

CORRECTION: We regret that the Technology Focus in Cold Facts Vol. 31 No. 1 misspelled the name of the fea-tured company. It should be Iris Tech-nology. The company has developed the Iris Cryocooler Electronics (ICE) product line, a suite of “plug-and-play” cryo-cooler control electronics designed to support both traditional life-long space and tactical cryocoolers with applica-bility spanning from microsats to deep space astronomy. www.iristechnology.com

International Particle Accelerator Conference (IPAC’15)May 3-8Richmond, VAhttp://2csa.us/cw

World Gas ConferenceJune 1-5Paris, Francehttp://2csa.us/br

Joint Army-Navy-NASA-Air Force (JANNAF) MeetingJune 1-5Nashville, TNhttp://2csa.us/cm

HEPTech Academia Meets Industry on CryogenicsJune 4-5Grenoble, Francehttp://2csa.us/d7

26th Space Cryogenics Workshop (SCW'15)June 24-26Embassy Suites-Biltmore, Phoenix AZwww.spacecryogenicsworkshop.org

CSA Tours at SCW’15June 27JW Marriott Starr Pass Resort, Tucson AZhttp://2csa.us/tours

CSA Short Courses at CEC/ICMCJune 28JW Marriott Starr Pass Resort, Tucson AZhttp://2csa.us/sc15

Cryogenic Engineering Conference/International Cryogenic Materials Conference (CEC/ICMC)June 28-July 2JW Marriott Starr Pass Resort, Tucson AZwww.cec-icmc.org

16th International Workshop on Low Temperature DetectorsJuly 20-24Centre de Congrès WTC, Grenoble, Francehttp://2csa.us/cg

24th IIR International Congress of RefrigerationAugust 16-22Yokohama, Japanhttp://2csa.us/c4

17th International Conference on RF SuperconductivitySeptember 13-18Whistler Conference Centre, Whistler, British Columbia, Canada

International Conference on Magnet Technology (MT 24)October 18-23Coex, Seoul, Koreahttp://2csa.us/c8

CGA Safety & Reliability of Industrial Gases, Equipment and Facilities SeminarOctober 20-21Intercontinental Hotel, Tampa FL

The 18th International Conference of the International Society of Cryosurgery (Cryo Egypt 2015)October 21-24Sharm El Sheikh, Egypthttp://2csa.us/ck

Gastech 2015October 27-30Singaporehttp://2csa.us/bu

2016

Particle Accelerator Conference (PAC’16)October 10-14Sheraton Towers, Chicago IL

www.cryogenicsociety.org/calendar

Upcoming Meetings & Events


Index of Advertisers26th Space Cryogenics Workshop . . . . . . . . . . . . . . . . . . 24

ACME Cryogenics, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Advanced Research Systems . . . . . . . . . . . . . . . . . . . . . . 11

American Magnetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Bauer Compressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

CAD Cut/Web Industries. . . . . . . . . . . . . . . . . . . . . . . . . . 11

CCH Equipment Co. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Chart Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Cryo Technologies . . . . . . . . . . . . . . . . . . Inside Front Cover

Cryoco LLC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Cryofab, Inc. . . . . . . . . . . . . . . . . . . . . . . Inside Back Cover

Cryogenic Control Systems . . . . . . . . . . . . . . . . . . . . . . . . 30

Cryogenic Machinery Corporation . . . . . . . . . . . . . . . . . . 31

Cryomech, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . Back Cover

CEC/ICMC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

CSA Short Courses at CEC/ICMC . . . . . . . . . . . . . . . . . . . 46

CSA Tours at SCW’15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

HPD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

International Cryogenics . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Janis Research Co., Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Lake Shore Cryotronics . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Linde Cryogenics/Linde Process Plants, Inc. . . Inside Back Cover

Magnatrol Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Master Bond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Meyer Tool & Mfg., Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Oxford Instruments Omicron NanoScience . . . . . . . . . . . 27

PHPK Technologies . . . . . . . . . . . . . . . . . Inside Front Cover

RegO Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

RICOR USA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

SGD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Sumitomo SHI Cryo America . . . . . . . . . . . . . . . . . . . . . . . 3

Sunpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

SuperPower Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Technifab. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Tempshield Cryo-Protection . . . . . . . . . . . . . . . . . . . . . . . 37

Thermax, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

WEKA AG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Cold Facts is the official technical magazine of The Cryogenic Society of America, Inc. 218 Lake Street • Oak Park IL 60302-2609Phone: 708-383-6220 Ext. 302 • Fax: 708.383.9337Email: [email protected] • Web: www.cryogenicsociety.org A non-profit technical society serving all those interested in any phase of cryogenicsSSN 1085-5262 • CSA-C- 3840 • April 2015 Printed in USA

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