NSLS-II Site Vibration Measurements...NSLS-II Site Vibration Measurements C. Spataro, Mechanical Engineering Group, NSLS-II Electron and X -ray Beam Stability Review, January 18-19,

1 BROOKHAVEN SCIENCE ASSOCIATES

NSLS-II Site Vibration Measurements

C. Spataro, Mechanical Engineering Group, NSLS-II

Electron and X-ray Beam Stability Review, January 18-19, 2018, Brookhaven National Laboratory, Upton, NY


Acknowledgement

L. Carr, W. Cheng, Y. Chu, R. Deng, L. Doom, T. Dilgen, J. Dvorak, N. Fukuto, I. Jarrige, B. Leonhardt, Shaftan, N. Simos, J. Skaritka, R. Smith, M. Sullivan, G. Wang, F. Willeke.


Many thanks to the following who’ve been instrumental in the hands-on vibration and thermal stability work over the past five years: J. Duff, A. Jain, F. Lincoln, V. Ravindranath, S. Sharma, W. Themann. An many thanks to the following who’ve offered their advice and support.


Mechanical Stability Issues at BNL

High performance goals of the new light sources require stringent mechanical stability of their equipment such as magnets, BPMs, slits, mirrors, monochromators, and detectors. The mechanical stability of these components can be compromised by site-wide ground vibrations, local vibration sources (pumps, motors, etc.), and fluctuations in air and water temperatures. This presentation will highlight the results of several studies at the BNL site to characterize ground vibrations and their correlations with the nearby expressway and railroad.



Outline 1. Introduction 2. Motivation for Stability Measurements 3. Sources of Instabilities 4. Ground Motion Measurements 5. Green Field Studies 6. NSLS-II Vibration Studies 7. Thermal Studies 8. BNL Site Studies 7. Mitigation Techniques 8. Future Improvements



Motivation for Stability Measurements Goal: Short term stability (AC) & Long term stability (DC ) •NSLS-II- low emittance and small beam size are needed to achieve greater intensity and brightness. Fast orbit correction can compensate for effects due to vibration and temperature but not all of it.


Mechanical RMS 4-50 Hz Thermal < 0.1 Hz.

Stability Requirements (Vibration and Thermal):

Requirements ΔX RMS(nm) ΔY RMS(nm)Magnet to Magnet < 157 < 22

Girder to Girder < 310 < 72BPMs < 100 < 100

Slits (over 8 hours) < 1 µm < 1 µm


Sources of Instabilities- Natural, Cultural, Electrical, and Mechanical

Natural Sources •Lunar Tides (Long Island -1000 miles of linear coast). •Solar Tides (Half the magnitude of lunar tides). •Earthquakes. •Wind. •Barometric pressure. •Seasonal changes Cultural Sources •Aircraft, helicopters (BNL has a heliport). •Automobile Traffic. (6000 miles of roadways) •Trains (700 miles of tracks) •People (~ 8 million on Long Island) •Pager system in NSLS-II ring. •Thermal sources •Construction


Electrical Sources • Power supply ripple (and

harmonics) • 60 Hz noise • Thermal sources – power

supplies,etc Mechanical Sources • AC handlers • Pump skids • Water flow/Liquid helium

induced vibrations • Water chiller tower • Vacuum pumps • Air temperature fluctuations


Ground Motion Measurements


Analysis: FFT is performed on time domain data Results: Integrated Displacement Time Profiles Integrated Displacement vs Frequency Power spectrum density (PSD) vs Frequency Correlation vs Frequency Plot

Instrument ManufacturerLower

Frequenccy Limit (Hz)

Upper Frequency Limit (Hz)

Seismometer Guralp 0.005 50

Geophone Sercel 1 1000

Accelerometer PCB 0.06 450

Guralp Seismometer Sercel Geophone


Ground Motion Measurements

• The ground motion below 4 Hz was assumed to be correlated over the length of the storage ring cell (25 m).

• Temperature fluctuation in the tunnel was specified to be ± 0.1º C.(in time)


1E-101E-091E-081E-071E-061E-051E-041E-031E-021E-011E+001E+01

1 10 100Dis

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NSLS-II Floor RMS Displacements on NSLS-II floor (2-30) Hz: 69 nm (30-100) Hz: 3 nm


Ground Motion Measurements– NSLSII SR Floor and Girder

The maximum day-time amplitude is ~ 5 times the minimum night-time amplitude

24 Hours



Green Field Vibration Studies- Locations


Green field vibration measurements were made at a number of locations during the day.

The term ‘greenfield’ was originally used in construction and development to reference land that has never been used (e.g. green or new).


Green Field Measurements


The vibration amplitude and short term time variation decreased with increasing distance from the LIE. The BNL East location were found to have the lowest vibrations that were measured.

(nm

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NSLS-II Vibration Studies LIE Car Count



Absolute Floor Vibration and Traffic Count


LIE Traffic Count Data 6/24/09-6/25/09 (DST)

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RMS Floor Motion (2-100 hz) and LIE Traffic Count vs TimeCenter of Each Pentant

Pentant 5 Cell 19 Wednesday 1/9/13-Thurs. 1/10/13

Pentant 4 Cell 13 Friday 1/11/13-Saturday 1/12/13

Pentant 3 Cell 7 Wednesday 1/16/13-Thursday 1/17/13



LIE Traffic Count

LIE Traffic Count


• Although the traffic data is from 2009, the current year’s basic traffic profile is expected to be similar.

• One possibility is that the main contribution to the increased vibrations is from heavy vehicles traffic, which may have a different time profile.

• DOT does not keep separate counts for heavy vehicles. • In June 2014, a private firm Tri-State Traffic Data, Inc. was contracted

to record and analyze via camera and software the east and west bound traffic on the LIE between exits 68 and 69.

• The traffic in each direction was further separated into 3 categories – motorcycles, cars or light trucks, and large trucks.

• Vibration measurements were carried out in parallel with these traffic count studies to facilitate a direct comparison of the vibration and traffic time profiles.

SR Floor Motion and Traffic Count




Experimental Floor Vibrations Levels vs LIE Total Traffic Count

It’s obvious that the total traffic is uncorrelated to the vibration levels seen on the experimental floor.


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Exper. Floor Vibration Levels vs LIE Eastbound Truck Count


The eastbound truck traffic shows a peak in the morning consistent with the vibration pattern but does not explain the second vibration peak in the afternoon.

Truck traffic peak and vibration peak @ 9AM

Second vibration peak @ 3 pm


Exper. Floor Vibration Levels vs LIE Westbound Truck Count


The westbound truck traffic shows a peak in the afternoon consistent with the vibration pattern. The westbound traffic persists beyond the time the vibration levels have been reduced, It’s possible the westbound trucks are empty and do not contribute significantly to the vibration levels.

Truck traffic peak and vibration peak @ 3 PM

Vibration levels have dropped


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NSLS-II Studies 2-ID Correlation Measurement 0’ Separation Between Seismometers on Floor


Courtesy of A. Jain


Integrated RMS displacement

Correlation between the two magnets Vibration measurement taken on two

farthest magnets on a single girder.

Good correlation between the two points for frequencies below 25 Hz

Relative Integrated RMS motion (vertical) between the magnets 2-100 Hz = 8 nm ;

Meets specification of < 25 nm.

5 m

NSLS-II Vibration Studies Relative Motion Between Magnets on a Single Girder-G4

Girder- Cell 7 G-4


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Correlation Plot Vibration measurement taken on two farthest magnets

on two separate girders: Cell 7, G2 and G4 Good correlation between the two points for frequencies

below 5 Hz Relative Integrated RMS motion between the magnets 2-

100 Hz = 28.8 nm,

Meets Girder-Girder Specification < 70 nm.

13 m

NSLS-II Vibration Studies Relative Motion Between Magnets on Two Separate Girders

Integrated RMS displacement


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NSLS-II Vibration Studies - Floor Motion Correlation

~ 13 m

• Floor motion correlated up to 4-5 Hz over a distance of ~ 13 m. • Preliminary data indicated good floor motion correlation below 2 Hz over a distance of 30 m

(covering one cell length). • Vibration amplification factor, from floor to girder/magnet in 2-100 Hz is approximately one. • Above 2 Hz, relative motion between magnet-magnet and girder-girder are within

acceptable limits. •



NSLS-II SR Tunnel Thermal Stability

Locations of the Temperature Sensors

Temperature Stability Specifications: • ± 0.1 ºC in time with 1-hour cycling. (Time) • ± 1 ºC over the entire tunnel. (Space) • 0.1 ºC/m Gradient



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20130508 Temperature Run Pentant 1 Temperature vs Time 1 Hour Period

RTD1RTD2RTD3RTD4RTD5RTD6RTD7RTD8RTD9RTD10RTD11RTD12RTD13RTD14RTD15RTD16RTD17RTD18RTD19RTD20RTD21RTD22RTD23RTD24RTD25RTD26RTD27RTD28RTD29RTD30

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2013 Temperature Stability in Pentant 1

Temperature variation over entire pentant = ±0.75C

A study at APS showed a strong correlation between temperature and corrector strength which led to an upgrade in their temperature control system.


SR tunnel temperature meets the full specification.


2017 Temperature Stability in Pentant 2


Current data shows a stability of 1.4 degrees which is clearly out of specification range. This is under investigation and could be a temperature control feedback issue.

1.4 Degree F


BNL Site Vibration Studies from 2011-2016 • SEB2 Building • Bldg 703 Lab • 23-ID- 90 mm dipole and vacuum chamber • 2-ID Monochromator • NSLS-II All pentants and service buildings • NSLS-II Mezzanine • 23-ID Chiller • Bldg 725 Computer Room • NSLS-II Cooling Tower • SLM Diagnostic girder • NSLS-II XBPM • Green field locations • X-Y Slit stages



BNL Site Studies NSLS-II SR Floor and Girder

Spike in vibration data at 2:30 A.M. Previously thought to be hardware/software glitch.

24 Hours



BNL Site Studies- RMS Displacement vs Time 1/15-1/16 Data taken in the SR Floor in Pentant 3 Cell 7

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23 minute duration

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BNL Site Studies- Increased Acquisition Time to 57 Minutes RMS Displacement (2-100 Hz)= 151 nm

Large Vibration duration= 12 minutes

• The duration and shape of the large vibration suggests a moving vibration source that approaches close to the BNL site and then moves farther away.

• This suggests a freight train.



Date Time Interval Probable Train12/4/2013 9:29-9:34 PM LIRR Leaf Crusher Eastbound12/5/2013 12:27-12:32 AM NYA RS-60 Eastbound12/12/2013 12:11-12:23 AM NYA RS-60 Eastbound12/12/2013 1:30-1:38 AM NYA RS-61 Westbound12/12/2013 2:44-2:50 AM LIRR Leaf Crusher Westbound

BNL Site Studies Investigating Source of Intermittent Late Night Vibrations on the NSLS-II SR Floor

•New York & Atlantic Rail (NY & A) who run the freight trains on the LIRR lines were contacted. •The freight train schedule is irregular but usually runs between the hours of 12- 3 AM. •Dates and the time intervals in question were sent to them. •Five out of five large vibration intervals matched their freight train schedule.

*

* * A leaf crusher train is used to wash and clean the tracks of an oily residue left by crushed leaves on the rail.



BNL Site Studies - IR Video Capture of LIRR Close to BNL

IR Camera 1 IR Camera 2


IR cameras positioned about 50 feet away from tracks on BNL property. Simultaneous vibration data was taken on experimental floor.


BNL Site Studies -Vibration Levels Measured on Experimental Floor and Timings of Various Types of Trains Passing Close to BNL Site.



BNL Site Studies NSLS-II Effects of Shaker On 17-BM Experimental Floor


Goal: Measure increase of RMS displacement of Experimental floor due to presence of chiller. Chiller cycled on and off every half hour.

Shaker Location in sample prep area

Geophone location near 17-ID hutch

Shaker

Steel table

Sercel Geophones

Distance between seismometer on floor next to shaker and the 17ID floor location is 25’

Vert Vert Horiz Horiz

DateTime Shaker Status Floor-17ID Floor Floor 17-ID Floor

2017/05/10 09:15:24 ON 117.8 108.2 49.2 57.12017/05/10 09:24:45 OFF 123.4 117.0 45.7 60.9

Note: Variation in absolute displacement over time is due to local disturbance and/or cultural background vibration source, ie, LIE truck traffic, local traffic, freight trains.

Conclusion: No dramatic increase in floor vibration when shaker is turned on.


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BNL Site Studies NSLS-II Cell 25 Experimental Floor


A noise spike at a frequency of 250 Hz was seen at cell 25 in the NSLS-II ring by the accelerator physics group. Goal: A vibration study was undertaken to see if this was observed on the experimental floor adjacent to cell 25

Conclusion : 250 Hz signature it is not coming from natural ground motion but probably induced from an unknown source.

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Examination of the RMS displacement does reveal there is a small sub-nanometer vertical disturbance at 250 Hz. (circled in red)


BNL Site Studies NSLS-II 3-ID HXN Goal: HXN 3-ID Experimenters are seeing a 0.13 Hz noise spike that is affecting their imaging resolution. Previous data taken in Pentant 3 Cell 7 with a Gurlap seismometer with a very low bandwidth (0.008 Hz) was examined.


According to C. Montag (BNL) & J. Rossbach (DESY) , this ‘7 second hum’ appears in all spectra at various labs around the world and is a ‘Microseismic peak around 1/7 Hz; caused by ocean waves hitting coasts.’- Handbook of Accelerator Physics and Engineering, Chao,et al. A spike is seen at a frequency of 0.12 Hz

1.00E-151.00E-141.00E-131.00E-121.00E-111.00E-101.00E-091.00E-081.00E-071.00E-061.00E-051.00E-041.00E-031.00E-021.00E-011.00E+00

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Integrated RMS Vertical Displacement vs FrequencyPentant 3 Cell 7 (20140225_105008)

Ch0

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Guralp Upper Bandwidth Limit =50 HzLower Bandwith Limit= .0083 Hz


BNL Site Studies NSLS-II 11-BM Vibration Study


Goal: Study the vertical vibration signature on the 11BM FOE and Hutch during the maintenance period to locate the source that’s causing a 200 micron fluctuation of the beam at rate of a 1 Hz during operations.

Conclusion : The spring-loaded screws for the kinematic mount for the 1st crystal were tightened resulting in the dampening of the vertical motion.

Before After

Measurements taken along the entire length of the beamline from the Front End to the sample chamber did not reveal a 1 Hz frequency.

11-BM Layout

(Photos taken from video - courtesy of Masafumi Fukuto)


BNL Site Studies NSLS-II SEB 2 Floor


Goal: Study the vertical vibration signature on the SEB2 floor in the approximate location of the future source and target for a two week period.

Seismometers were located 13.1 M apart between source and target locations.

Conclusion : Vibration results led to a re-design of the experiment.

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Ch0 Detector

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Thanksgiving Day

Lab Closed

Black Friday

Vertical displacement varied from 15 to 100 nm (not counting vibration spikes)


BNL Site Studies- SIX Spectrometer


(Courtesy of Ignace Jarrige)


BNL Site Studies- SIX Spectrometer


(Courtesy of Ignace Jarrige)


Detected Sources of Instabilities • Lunar Tides • Wind • Local automobile traffic • LIE truck traffic • Freight train traffic • People • 60, 120 Hz noise • Vacuum pumps • Water flow • Air temperature fluctuations



Mitigation Techniques • Perform vibration and thermal studies before the installation of

equipment as was done with the SIX spectrometer. • Re-pave BNL roads and portions of the LIE if possible. • Implement mechanical vibration reduction techniques on beam

components (tables, XY Stage, stands, BPMs, etc). • Redesign/reroute plumbing and adjust water flow to minimize

mechanically induced vibrations. • Pour deeper foundations to minimize vibrations. • Minimize equipment with high heat load (power supplies, etc) • If specifications change or traffic increases in the future, other mitigation

techniques should be studied.



Future Developments • Develop a non-contact interferometer-based inertial displacement

sensor that can feed the BPM motion information to the control system in real time to compensate for ground motion.

• As a first step, implement a BNL vibration early warning system for experimenters which would be used to insure the data they are taking is valid.

• Eventually develop a permanent vibration monitoring system throughout the BNL site available to all scientific facilities and users.

• Installation is underway to install permanent RTDs in tunnel floor above the vehicle tunnel to study the temperature gradient in the concrete slab.

• Install permanent thermal sensors to study temperature fluctuations inside and outside of buildings.



The End



Supplemental Slides



Courtesy: Animesh Jain, Superconducting Magnet Division, BNL , (3/20/2013) Electron and X-ray Beam Stability Review, January 18-19, 2018,

Brookhaven National Laboratory, Upton, NY


Courtesy: Animesh Jain, Superconducting Magnet Division, BNL, (3/20/2013) Electron and X-ray Beam Stability Review, January 18-19, 2018,



Courtesy: Animesh Jain, Superconducting Magnet Division, BNL, (3/20,2013) Electron and X-ray Beam Stability Review, January 18-19, 2018,


Documents

NSLS-II Site Vibration Measurements...NSLS-II Site Vibration Measurements C. Spataro, Mechanical Engineering Group, NSLS-II Electron and X -ray Beam Stability Review, January 18-19,