Design and thermal analysis of the cooling system of … Design and thermal analysis of the cooling system of the ... energy,timeandpositionofimpact ... Chapter 6 Conclusion The goal

Universita di Pisa

Dipartimento di Ingegneria Civile ed Industriale

Corso di Laurea Magistrale in Ingegneria Meccanica

Tesi di laurea magistrale

Design and thermal analysis of the cooling system of theelectromagnetic calorimeter of the Mu2e experiment at Fermilab

Candidato:

Eugenio BenedettiRelatori:

Prof. Ing. Marco BeghiniProf. Ing. Bernardo Disma MonelliProf. Simone DonatiIng. Fabrizio Raffaelli

Anno Accademico 2017–2018

grazie alle emozionia tutte le emozioni

Augusto Daolio

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Abstract

This Master Thesis is dedicated to the design of the electromagneticcalorimeter of the Mu2e experiment at Fermilab. Mu2e has the ambitiousgoal to search for the neutrinoless coherent conversion of the muon to anelectron in the field of a nucleus. The observation of this physics processwould provide the evidence that the theory, called Standard Model, whichdescribes the interactions among elementary particles is not complete. TheMu2e calorimeter has the fundamental function to detect and measure theenergy, time and position of impact, of the electrons and identify the signalof conversion electrons, which is expected to be extremely rare, from theelectrons produced in the muon decays. The calorimeter has been designedand will be constructed by a collaboration among the Istituto Nazionale diFisica Nucleare (INFN), the California Institute of Technology (CalTech) andFermilab (FNAL). I have worked for five months at INFN in Pisa and visitedFermilab in June 2018. The calorimeter is part of a complex experimentalapparatus composed of several independent and complementary detectors,including a straw-tracker and a plastic scintillator cosmic-ray veto.

• Chapter 1 and 2 report the description of the Mu2e experiment andelectromagnetic calorimeter. The following Chapters describe my workwhich has been dedicated to the design of the cooling system of thecalorimeter electronics. This is a fundamental problem in Mu2e, sincethe experiments is operated in vacuum inside a cryostat.

• Chapter 3 reports the thermal analysis of a SiPM (Silicon Photo Mul-tiplier). This analysis is important to simulate to make sure the SiPMis maintained at the operational temperature of 0 ◦C.

• Chapter 4 reports the mechanical tests performed on PEEK (PolyEtherEther Ketone): a tensile test to check the producer data but more im-portant there are tests about adhesive bonding PEEK-PEEK. Differentadhesive and different kind of joint were tested.

• Chapter 5 describes the study of the thermal contraction of the elec-tronic cooling lines. These are linked with the PEEK backplate byseveral M2 tap bolt and their function temperature is of −10 ◦C whilethe backplate keep an higher temperature (at least during the kick off).

• Chapter 6 reports my conclusions of my work.

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Ringraziamenti

Ringrazio il professor Beghini, stimato docente, per gli aiuti e la formazioneche mi ha fornito in questi anni e per questa tesi.

Ringrazio il professor Monelli per la cordialità con la quale mi ha sempreaccolto e mi ha aiutato a affrontare i problemi.

Ringrazio il professor Donati per la minuziosa cura e meticolosità con laquale mi ha seguito in questo percorso all’INFN.

Ringrazio Fabrizio Raffaelli, un maestro di competenza, dal quale ho potutoapprendere un po’ di tutto nei più disparati argomenti stando nel suo ufficio.

Ringrazio poi mio padre e mia madre, semplici, unici, per non avermi maifatto mancare niente e per il massimo impegno e la smisurata generosità concui si son dedicati a me, per aver sempre creduto in me, aiutandomi a crederein me stesso.

Ringrazio poi il resto della famiglia, zio, zia e tata, sempre presenti, sempredisponibili, per avermi trattato con il massimo affetto.

Un grazie speciale poi va a nonnina, unica nel suo genere, nella sua follia.

Non ringrazio gli amici miei di sempre Peec, che odio, e Monta, quellosquallido, compagni di ogni avventura, per avermi sempre messo i bastonitra le ruote e basta e per non aver mai preso nulla sul serio. . .ma è così chedeve essere.

Ringrazio invece gli altri maschiosi, Barga, Cami, Enrico e Filippo per le di-verse esperienze condivise nel corso dei vari anni di amicizia e per i moltepliciricordi che ho legati ad ognuno di loro, Catania tra tutti.

Un grande ringraziamento va a Paolone, non solo un compagnio di studi inquesto ultimo anno, e a tutte le altre persone conosciute all’università, Lau,Gas, Tambe, Leo, Giulio, Mau, l’Agliax, il Barto e Ciccio per le molteplicirisate fatte, le patte e il deridersi continuo. Con alcuni ho potuto condividerele intense sessioni di studio nella fortunata casa di Torre Del Lago: un ricordocaro e indelebile.

Ringrazio le persone che conosco da davvero tutta la mia vita, Nico, Lavi,Ruben e l’ing. Batini che di sicuro faranno il possibile per essere presenti aquesta mia laurea.

Ringrazio tutto il gruppo Apnea Academy di Pisa per la passione per ilmare che mi ha trasmesso, per il rilassamento che mi ha dato e per avermiaccompagnato a −28.7 m all’Elba.

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Un altro ringraziamento va all’ E-Team Squadra Corse per il senso di ap-partenza a una grande squadra e per le emozioni provate in gara.

Probabilmente avrò scordato qualche sassolino in questi ringraziamenti, per-sone che sono state importanti per il percorso universitario e non solo.Ringrazio quindi chiunque mi abbia dato una mano in questi miei impor-tanti anni.

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Contents

1 The Mu2e experimental apparatus 11.1 The Standard Model . . . . . . . . . . . . . . . . . . . . . . . 1

1.1.1 The muon decays . . . . . . . . . . . . . . . . . . . . . 21.2 The Fermilab accelerator complex . . . . . . . . . . . . . . . . 3

1.2.1 The accelerators chain . . . . . . . . . . . . . . . . . . 41.3 The Mu2e experimental apparatus . . . . . . . . . . . . . . . 4

1.3.1 Production Solenoid . . . . . . . . . . . . . . . . . . . 61.3.2 Transport Solenoid . . . . . . . . . . . . . . . . . . . . 61.3.3 Detector Solenoid and Mu2e detector . . . . . . . . . . 6

2 The Mu2e electromagnetic calorimeter 112.1 Conceptual design . . . . . . . . . . . . . . . . . . . . . . . . 112.2 Technical specifications . . . . . . . . . . . . . . . . . . . . . . 122.3 Calorimeter mechanics . . . . . . . . . . . . . . . . . . . . . . 13

2.3.1 The front end unit . . . . . . . . . . . . . . . . . . . . 162.4 Calorimeter electronics . . . . . . . . . . . . . . . . . . . . . . 16

2.4.1 SiPMs and front end electronics . . . . . . . . . . . . . 172.4.2 Data acquisition, power and monitoring electronics . . 17

2.5 Calorimeter electronics cooling . . . . . . . . . . . . . . . . . 18

3 Thermal analysis of the SiPM 233.1 SiPM simulation . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.1.1 SiPM model . . . . . . . . . . . . . . . . . . . . . . . . 243.1.2 Boundary condition . . . . . . . . . . . . . . . . . . . 253.1.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.2 Thermal model of the front end unit . . . . . . . . . . . . . . 263.2.1 The glue . . . . . . . . . . . . . . . . . . . . . . . . . . 283.2.2 The SiPM support . . . . . . . . . . . . . . . . . . . . 293.2.3 The problem of radiation from the CsI crystals . . . . 293.2.4 Boundary conditions of the thermal analysis . . . . . . 30

3.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

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viii CONTENTS

4 PEEK tensile and gluing tests 354.1 PEEK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364.2 Testing machine . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4.2.1 Load cell and grips . . . . . . . . . . . . . . . . . . . . 364.3 Tensile tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4.3.1 Preparation of the PEEK specimens . . . . . . . . . . 394.3.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.4 Stepped joint . . . . . . . . . . . . . . . . . . . . . . . . . . . 424.4.1 Tested adhesives . . . . . . . . . . . . . . . . . . . . . 434.4.2 Preparation of the specimen . . . . . . . . . . . . . . . 444.4.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . 47

4.5 Double scarf joint . . . . . . . . . . . . . . . . . . . . . . . . . 474.5.1 Test of the adhesive thickness . . . . . . . . . . . . . . 474.5.2 Joint preparation . . . . . . . . . . . . . . . . . . . . . 484.5.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

5 Thermal deformation studies 535.1 The problem . . . . . . . . . . . . . . . . . . . . . . . . . . . 535.2 Preliminary model . . . . . . . . . . . . . . . . . . . . . . . . 55

5.2.1 Two types of cooling lines . . . . . . . . . . . . . . . . 555.3 Preliminary design solution . . . . . . . . . . . . . . . . . . . 56

5.3.1 Free play . . . . . . . . . . . . . . . . . . . . . . . . . 565.3.2 Layout constraint . . . . . . . . . . . . . . . . . . . . . 57

5.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6 Conclusion 59

A Technical drawings 61

B Datasheet 67

List of Figures 87

List of Tables 91

Bibliography 93

Chapter 1

The Mu2e experimentalapparatus

In this Chapter we summarize the physics motivations and the experimen-tal techniques used by the Mu2e experiment at Fermi National AcceleratorLaboratory (FNAL or Fermilab). We also provide a brief overview of theFermilab accelerator facility necessary to provide the muon beam used bythe Mu2e experiment.

The Italian National Institute of Nuclear Physics (INFN) is responsi-ble of the design and construction of the detector named "electromagneticcalorimeter" in collaboration with the California Institute of Technology(Caltech) and Fermilab. This project will be completed within the year2020, well in time for the beginning of Mu2e data taking planned for theyear 2021.

1.1 The Standard Model

The Standard Model of the Particle Physics is the theory which providesa satisfactory model of three of the four known fundamental forces (elec-tromagnetic, weak and strong) which determine the interactions among theknown elementary particles. Many Standard Model predictions have beenexperimentally verified with high precision.

Figure 1.1 on the following page shows the table with the currently knownelementary particles. Fermions are the elementary constituents of matter,while bosons are the mediators of the fundamental interactions. Fermionscan be divided in quarks and leptons. Quarks combine to form particlescalled hadrons (such as protons and neutrons, which are the constituentsof the atomic nuclei). Leptons are composed of two classes: charged andneutral (also known as neutrinos); while charged leptons interact with otherparticles mostly through electromagnetic and weak interactions, neutrinosdo not have electric charge; hence they interact only via weak interactions.

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2 CHAPTER 1. THE MU2E EXPERIMENTAL APPARATUS

Figure 1.1: Summary table of the elementary constituents of matter,quarks, leptons and gauge bosons (image courtesy of Fehling,Dave. The Standard Model of Particle Physics: A Lunchbox’sGuide. The Johns Hopkins University).

Therefore, they are difficult to observe or measure.Both quarks and leptons are divided into three generations. The first

one includes the electronic leptons: the electron (e) and the electron neu-trino (νe), the second one the muonic leptons: the muon (µ) and the muonneutrino (νµ), and finally the third one the tauonic leptons: the tau (τ) andtauonic neutrino (ντ).

1.1.1 The muon decays

Muons and taus are unstable particles, unlike the electron which is stable.The muon decays with a probability approximately of 100 % to a muon neu-trino (νµ), an electron (e) and an electron antineutrino (νe). In symbols,the muon decay is represented as follows µ→ νµeνe. Rarely, also other par-ticles with a net charge equal to zero may be produced in the muon decay(e.g. a photon, or an electron-positron pair). Searches for Charged LeptonFlavor Violating (CLFV) processes, such as the decay µ− → e−γ have, sofar, yielded null results. CLFV processes are expected within the StandardModel with a probability < 10−50 (Figure 1.2). With the current level ofexperimental precision, such effects are obviously well beyond our experi-mental reach. Although the Standard Model has been accurately tested, itis probably an incomplete theory. Several extensions of the model includeCLFV processes and allow for the coherent neutrino-less conversion to anelectron in the field of a nucleus with rates within the reach of next gen-eration experiments, including the muon-to-electron conversion experimentMu2e at Fermilab.

1.2. THE FERMILAB ACCELERATOR COMPLEX 3

(a) Feynman diagramsfor the coherent muonconversion to an elec-tron in the field of anucleus. The energy ofthe produced electronwould be approxi-mately the muon restmass (corrected for thenucleus recoil and thenucleus bond energy)which is approximately104.9MeV

(b) Feynman diagram forthe Charged LeptonFlavour Violatingmuon decay µ→ eγ

Figure 1.2: Feynman diagrams for Charged Lepton Flavour Violating(CLFV) processes µ+N → e+N and µ→ eγ (source: Mu2eexperiment data center).

Mu2e has been designed and is currently being constructed at Fermilabto search for the neutrino-less muon conversion to an electron in the field ofan aluminum nucleus. The current experimental limit on the search of thisprocess has been set at 10−12 by the SINDRUM II experiment at the PaulScherrer Institut at Zurich.

The sensitivity of the Mu2e experiment will allow the observation of themuon conversion events if the probability of this process is at the level of10−17. If no event is observed, Mu2e will set a limit on the probability atthe level of 10−17 which will be an improvement of four orders of magnitudeover the current experimental limit. The beginning of Mu2e data taking isplanned for the year 2021 and it will continue for about three years. FutureMu2e upgrades will improve the experimental sensitivity by a factor of 10.

1.2 The Fermilab accelerator complex

Fermilab is located in Batavia, about 50 km west of Chicago, Illinois (USA).It was founded in 1967 as a US Department of Energy Laboratory and sinceits foundation it is part of the Universities Research Association (URA).Since 2007 the laboratory is operated by the Fermilab Research Alliance(FRA), a partnership between University of Chicago and the URA. Thename “Fermilab” was given to to the Laboratory in 1974 in honour of EnricoFermi, an important italian physicist who has won the Nobel Prize in 1938.

Since its founding Fermilab has always played a fundamental role in


the high energy physics scenario. Among its achievements we mention thediscovery of three of the four particles of the third generation of the StandardModel: the bottom quark (1977), the top quark (1995) and the tauonicneutrino (2000).

1.2.1 The accelerators chain

The accelerator complex is divided into five steps, which are, in order:

• A Cockcroft-Walton generator, which ionizes hydrogen gas by flowingit through a container clad with molybdenum electrodes: a match-box sized, oval-shaped cathode and a surrounding anode, separated by1 mm and kept in place by glass ceramic insulators. A magnetron (athermionic valve) is used to generate a plasma to form H– ions nearthe metal surface. The generetor applies a 750 keV electrostatic fieldwhich accelerates the ions out of the container.

• A Linear Accelerator (also called Linac), which accelerates the ions to400 MeV (so they reaches a velocity around the 70 % of the light speed).After they got this energy, the ions go across a carbon foil, which stripsoff the electrons transforming them into a H+ ions (protons) beam.

• The Booster Ring, a 468 m diameter ring where the beam is acceler-ated to its definitive energy, about 8 GeV, travelling along the Boosterapproximately 20 000 times in 33 ms and accumulating energy at eachcycle. The beam can run a circular path thanks to magnets.

• The Main Injector Recycler Ring, a 3.2 km circumference where theprotons are stacked and bunched by a 2.5 MHz radio frequency system.

• The Delivery Ring, where the bunches are slowly extracted and redi-rected to the Mu2e detector by a dedicated beamline.

1.3 The Mu2e experimental apparatus

The layout of the Mu2e detector is shown in Figure 1.4 on the next page. Themost relevant feature of the muon beamline is the Superconducting SolenoidMagnet System. The inside of the solenoids is evacquated to 10−4 torr to limitthe backgrounds due to the interactions between muons and gas particles.The solenoid and the rest of the apparatus can be schematically divided intoseveral subsystems that are described below.

1.3. THE MU2E EXPERIMENTAL APPARATUS 5

Figure 1.3: The Fermi National Accelerator Laboratory.The Main Injector tunnel is visible in the foreground, while the Tevatronone is visible in the background: it has been the most powerful particleaccelerator for many years before the costruction of the Large Hadron

Collider (LHC) at CERN in Geneva.

Figure 1.4: The Mu2e experimental apparatus.


1.3.1 Production Solenoid

The Production Solenoid is a high field magnet that generates a gradedsolenoidal field varying smoothly from 5 T to 2.5 T along its axis. this gradi-ent is achieved by dividing the solenoid in three axial coils with a decreasingnumber of windings, which are made respectively using three, two and twolayers of high-current, low inductance aluminium-stabilized NiTi cable: thismaterial allows for effcient energy extraction during a quench, requires fewerlayers to achieve the required field strength and minimizes thermal barriersbetween the conductor and cooling channels. The solenoid is complessivelyaround 4 m long with an inner bore of approximately 1.5 m. A heat and ra-diation shield, constructed from bronze, will line its inside to limit the heatload in the cold mass from secondaries produced in the production targetand to limit radiation damage to the superconducting cable.

Refering to the Figure 1.4, the 8 GeV proton beam enters in the Pro-duction Solenoid through the low-field side, sloped by a certain slight anglerespect to its axis. The beam is pulsed at approximately 0.6 MHz in orderto reduce the background caused by secondary beam particles. Inside thesolenoid near its centre the beam impact in the production target, which ismade of tungsten, radialy cooled, with a diameter of 12.6 mm and 16 cmlong. This impact generate a large amount of particles, including pions, thatdecay into muons. Remnant protons that are not absorbed by the targetand secondary produced particles exit at the high field end of the solenoid.Backscattered muons and pions in the forward direction with angles greaterthan 30° respect to the solenoid axis are captured by the higher field andmoved along the detector.

1.3.2 Transport Solenoid

The function of the Transport Solenoid is to transport 1011 muons per secondto be stopped in the secondary target located in the Detector Solenoid. Thisbeam line includes the collimators and anti-proton stopping window in theTransport Solenoid, proton and neutron absorbers, beam stop, and vacuumsystem. The Transport Solenoid filters the particle flux producing a momen-tum < 0.08 GeV/c and charge-selected muon beam, with a good reductionof the contamination from e±; µ+; π±; p and p during the detector live-time.

1.3.3 Detector Solenoid and Mu2e detector

The muon stopping target is located in the upstream section of the DetectorSolenoid which has a graded magnetic field to nearly double the acceptancefor conversion electrons and reject residual backgrounds. The baseline alu-minium target is made of 17× 0.02 cm thick disks (Figure 1.5).

The Mu2e straw-tracker and electromagnetic calorimeter are placed in-side the volume of the Detector Solenoid. The Mu2e collaboration has de-


Figure 1.5: The Mu2e stopping target. It is made of 17 aluminum disks,0.2 mm thick, spaced 5.0 cm apart along the Detector Solenoidaxis. The disks radii decrease from 8.3 cm at the upstream endto 6.53 cm at the downstream end.

cided to use a tracker design similar to the one developed by the MECOcollaboration (Figure 1.6). The tracker resides in a uniform 1 T solenoidalmagnetic field and is kept in a 10−4 torr vacuum to reduce the interaction ofparticles with residual gas to a negligible level. This detector reconstructsparticle tracks with high efficiency and measures the parameters of the heli-cal trajectories with high resolution. Since multiple scattering in the trackerdominates the resolution on the measurement of the helix parameters, themechanical structure of the detector has to be extremely light. A furthersource of uncertainty is due to pattern recognition errors. This effect mayproduce tails in the high-energy region of the resolution function. The trackeris made of straw drift tubes and is called T-tracker because the straws aretransverse to the axis of the Detector Solenoid. The basic detector elementis made of a 20 µm sense wire inside a straw tube filled with gas. The strawsare 5 mm diameter tubes made of 15 µm thick metallized Mylar. The trackerhas ∼ 20000 straws arranged into 18 measurement stations across the ∼ 3 mtracker length. Planes consist of two layers of straws, to improve efficiencyand help overcome the classic “left-right” ambiguity. A 1 mm gap betweentwo consecutive straws allows for manufacturing tolerance and expansiondue to gas pressure. A ring at large radius, outside the active detector re-gion, supports the straws. Each straw has one preamplifier and one time todigital converter on both sides, to measure the signal arrival time on bothsides, and uses also analog to digital converters for the measurement of thetotal integrated charge used for particle identification. The tracker is de-signed so that only electrons with energy above approximately 53 MeV arein the detector acceptance. They are approximately only 3% of the totalflux of electrons from muon decays-in-orbit. Since momentum resolution iscrucial to suppress several critical backgrounds, the tracker is required to


have a momentum resolution better than 180 keV. The Mu2e calorimeterprovides additional energy, position, and timing information for particlesthat have been reconstructed by the tracker. The electromagnetic calorime-ter and the straw-tracker use different physical processes and technologies toperform their measurements, so the sources of error from the two systemsare not correlated. This helps to reduce backgrounds and gives a cross checkto verify the quality of signal events. The calorimeter operates in the samesolenoidal 1 T magnetic field and 10−4 torr vacuum as the tracker. It handlesa large flux of particles, mostly low energy background of protons, neutronsand gamma rays produced by muon captures in the stopping target. It alsohandles a large flux of electrons from muons decaying in the atomic orbit inthe aluminum stopping target and other particles during beam injection. Amore detailed description of the calorimeter is reported in Chapter 2.

Figure 1.6: Mu2e tracker layout. Only electrons with energy above 53 MeVare recon-structed. Electrons with lower energy spiral in thenon-instrumented central region (source: Mu2e experimentdata center).

The Mu2e detectors include the Trigger and Data Acquisition (TDAQ)subsystems, which provide hardware and software to record the digitizeddata from the detectors. These data are delivered to online and offline pro-cessors for further analysis. The TDAQ also synchronizes and controls thedetector operations. In a streaming mode, the off-detector bandwidth re-quirement for the DAQ is estimated to be approximately 100 GBytes/sec.The TDAQ combines information from all detector data sources and appliesfilters (triggers) to reduce this rate by a factor of several thousand beforedata can be delivered to offline storage.


Figure 1.7: Map view of the Mu2e experimental area. The muon beamline,the Production Solenoid, the Transport Solenoid and DetectorSolenoid are clearly visible.


Chapter 2

The Mu2e electromagneticcalorimeter

The Mu2e detectors have been designed to reject background to a level con-sistent with a single event sensitivity for the coherent conversion of the muonto electron of the order of 10−17. The electromagnetic calorimeter is a funda-mental link in the chain of background rejection. A background of particularimportance is due to false tracks due to pattern recognition errors resultingfrom the high density of hits in the tracker. Accidental combination ofhits from low energy particles may erroneously combine into a trajectoryconsistent with a higher energy electron and imitates a signal. Thus, theprimary function of the Mu2e calorimeter is to provide a redundant set ofmeasurements to complement the tracker information and contribute to re-ject backgrounds due to tracking errors.

2.1 Conceptual design

Electrons produced in the muons decays stopped in the aluminum target fol-low helical trajectories in the solenoidal magnetic field and interact with thecalorimeter with a maximum energy in the 100 MeV range. In this energyregime, a total absorption calorimeter should use a homogeneous and con-tinuous medium to fulfill the Mu2e energy and time resolution requirements.The sensitive material could be either a liquid, such as xenon (Xe), or a scin-tillating crystal. The Mu2e collaboration has chosen the scintillating crystaltechnology. Several types of crystals have been considered, including bariumfluoride (BaF2) and cesium iodide (CsI). The baseline design (Figure 2.1)uses an array of less expensive undoped CsI crystals arranged in two annulardisks. Each crystal is read out by two large-area solid-state photodetectorsSiPMs (Figure 2.2) which are preferred to the standard photomultipliers be-cause the calorimeter operates in a 1 T magnetic field. While front endelectronics is mounted on the rear side of each disk, voltage distribution,

11

12 CHAPTER 2. THE MU2E ELECTROMAGNETIC CALORIMETER

slow control and data acquisition boards are hosted in 20 crates placed onthe lateral surface of the disks. A laser flasher system provides light to eachcrystal to perform relative calibration and for monitoring. A circulating liq-uid radioactive source system housed by the Source plate provides absolutecalibration and allows to determine the absolute energy scale. The crystalsare supported by a structure composed of two disks, the Inner ring and theOuter ring, which can be moved along the beam line on horizontal rails.

Figure 2.1: Exploded CAD view of one disk of the Mu2e electromagneticcalorimeter (source: Mu2e experiment data center).

(a) SiPM front view. (b) SiPMside view. The 8 pins con-nect the sensor to the front endelectronic board.

Figure 2.2: SiPM prototype produced by HamamatsuTM

2.2 Technical specifications

The primary function of the electromagnetic calorimeter is to measure elec-tron energy, position and time of impact. This information is vital to improvethe particles trajectories reconstruction performed by the straw tracker. The

2.3. CALORIMETER MECHANICS 13

goal is to minize the contamination of false tracks due to a spurious combina-tion of hits. Moreover, the calorimeter should provide useful information tothe trigger for the online data selection. Simulation shows that this perfor-mance is achieved if the detector has the following technical specifications:

• energy resolution of 5% at 100 MeV to confirm the electron momentummeasurement performed by the tracker;

• timing resolution better than 0.5 ns to ensure that energy deposits inthe calorimeter are in time with the hits reconstructed in the tracker;

• position resolution better than 1 cm to allow a comparison of the posi-tion of the energy deposits to the extrapolated trajectories of the tracksreconstructed by the tracker;

• the calorimeter should provide additional data that can be combinedwith the informations provided by the tracker to improve the muon-electron separation;

• the calorimeter should provide a trigger, either in hardware, or in soft-ware, or in firmware, that can be used to identify and select eventswith significant energy deposits;

• the calorimeter must operate in the hostile, high-rate, Mu2e environ-ment and must maintain its functionality intact for radiation expo-sures up to 20 Gy/yr per crystal and for a neutron flux equivalent to10× 1011 n1MeVeq/cm2.

2.3 Calorimeter mechanics

The two calorimeter disks are placed inside the Detector Solenoid. Each diskhas an inner radius of 374 mm, an outer radius of 600 mm, and is made of674 crystals. The crystals are 200 mm long with a square base and a sidelength of 34 mm. Each crystal is wrapped with a layer 0.15 mm thick madeof a Tyvek®reflective film to maximize the light transport along the crystaland minimize cross-talk among crystals.

The mechanical structure of each disk is made of two coaxial cylinders(FIgure 2.5).The inner cylinder is made of carbon fiber in order to minimizethe amount of passive material in the region where spiralling electrons aremostly concentrated. The outer cylinder can be as robust as required tosupport the crystals load and is made of aluminum. Each disk has two coverplates: one is placed upstream and faces the beamline, the other one is placeddownstream. The plate facing the beam is made of a low radiation lengthmaterial in order to minimize the electron energy deposit and preserve theelectron energy measurement. It has been designed to accommodate also the


calibration source. The other plate, called backplate, supports the front endunits and their cooling system.

The boards which provide the power to the front end electronics andSiPMs and perform the digitization of the SiPMs signals are hosted in the20 DAQ crates (Figure 2.4) placed in the radially external region of the disks(10 for each disk). Each DAQ crate hosts 9 boards. In order to gain as muchspace as possible between the disks and to allow for an easier access to thefront end electronics, the crates are placed on the external side of the disks.A view of the calorimeter is shown in Figure 2.3.

One crucial function of the mechanical structure is to provide adequateheat dissipation for the photosensors readout electronics and the electronicboards used for data acquisition, power and monitoring. This is a criticalfunction since the calorimeter operates in vacuum and the electronic powerhas to be dissipated primarily through thermal conduction. To this purpose,the electronics is placed in thermal contact with structures where coolingpipes are routed. The cooling station is composed of pumps and a chillerand is placed outside the cryostat.

Figure 2.3: CAD model of the Mu2e electromagnetic calorimeter. The 20custom crates which host the boards for voltage distribution,slow controls and data acquisition are shown in grey and green;the calorimeter can be moved along the beamline on a horizon-tal rail (source: Mu2e experiment data center).

2.3. CALORIMETER MECHANICS 15

Figure 2.4: CAD model of one DAQ crate (source: Mu2e experiment datacenter).

(a) Calorimeter front face. (b) Calorimeter rear face.

Figure 2.5: CAD model of one disk of the calorimeter (source: Mu2e ex-periment data center).


Figure 2.6: CAD model of one front end unit. The brown structure is themechanical support of the SiPMs and the front end boards.

2.3.1 The front end unit

The front end unit of the calorimeter is composed of the parts shown inFigure 2.6:

• One CsI crystal : the electrons impacting the crystal frontal surfacepenetrate the material and generate an electromagnetic shower; thephotons produced by scintillation diffuse through the crystal volumeand exit from the rear side;

• two SiPMs facing the rear side of the crystal and converting the lightproduced in the scintillation into electric signals;

• two front end boards (or FEE boards): each board is electrically con-nected to one SiPM ; it provides the power to the SiPM and amplifiesthe SiPM signals. The amplification has to be performed in the im-mediate proximity of the SiPM otherwise the very weak SiPM signalwould be lost in the electric noise;

• One mechanical support made of copper to support the SiPMs and theFEE boards.

2.4 Calorimeter electronics

The calorimeter electronics can be ideally divided in two subsystems withdifferent functions and locations.

The first subsystem is composed of the SiPMs and FEE boards, and isplaced on the rear side of the crystals. The second subsystem is composed

2.4. CALORIMETER ELECTRONICS 17

of the data acquisition boards, which perform the digitization of the ana-log signals received from the front end boards, provide power and performmonitoring of the front end electronics. The boards are hosted in the DAQcrates placed on the lateral side of the calorimeter.

2.4.1 SiPMs and front end electronics

The interaction between an impinging electron and a CsI crystal generatesan electromagnetic shower and the photons resulting from scintillation dif-fuse through the crystal towards the photosensors. Every crystal has theSiPMs on its backside to convert light into electric signals. There are twoSiPMs per crystal electrically connected to two FEE boards. The reason forthis redundancy is to provide a more robust measurement and to avoid dataloss if one SiPM ails during data taking. The resulting total number of photo-sensors is 1348 per disk. Commercial SiPMs produced by HamamatsuTM willbe used. In order to study the performance of the front end cooling system,the knowledge of the thermal properties (including the thermal conductivity)of the SiPMs is necessary. The FEE boards use several discrete components,including custom chips, named Amp-HV, which provide local linear regula-tion to the SiPMs bias voltage and receive and amplify the electric signalsreceived from the SiPMs as a response to the scintillation light. Groups of16 Amp-HV chips are controlled by one dedicated ARM controller placed onone interface board hosted in a DAQ crate that distributes low voltage andhigh voltage reference values, and sets and reads back the locally regulatedvoltages. The Amp-HV is a multi-layer double-sided discrete componentboard that performs the two tasks of amplifying the signal and providing alocally regulated bias voltage, and significantly reduces the noise loop-area.The two functions are independently executed in a single chip-layer, in theAmp and the HV side respectively. The Amp-HV chip has been developedby the Electronics Design Department of the INFN Laboratori Nazionali diFrascati (LNF). The required characteristics of the preamplifiers are:

• high amplification with low noise;

• fast signal rise and fall times for good time resolution and pileup re-jection;

• low detection threshold at the MeV level;

• functional in a rate environment of 200 kHz per channel;

• low power consumption.

2.4.2 Data acquisition, power and monitoring electronics

The analog signals produced by the front end electronics are transmitted tothe data acquisition boards hosted in the DAQ crates. Since the main func-


tion of the data acquisition boards is to digitize and transmit the analog sig-nals to the global Mu2e data acquisition, these boards are named “waveformdigitizers”. Additional boards are necessary to provide and distribute powerto the front end boards, and to monitor photosensors and front end electron-ics performance. These boards are named “interface boards”. In the currentdesign, there are 10 DAQ crates per disk, and each crate hosts 8 waveformdigitizers and 8 interface boards placed one next to the other. The wave-form digitizers use Field Programmable Gate Arrays (FPGA) and discretecomponents, including DC-DC converters and Analog to Digital Converters(ADC). The interface board uses voltage regulators and one ARM controllerto provide the logic necessary to control the front end boards.

2.5 Calorimeter electronics cooling

Since the calorimeter is operated in an experimental area at the pressure of10−4 torr, a dedicated cooling system based on the flux of a low tempera-ture cooling fluid is necessary. In the current design, the cooling systems ofthe front end units and of the DAQ crates are almost completely indepen-dent: they are connected to the same cooling and pumping stations but withindependent manifolds.

The DAQ cooling system (Figure 2.7) is obtained directly in the lateralwalls of is obtained directly in the lateral walls of the cardlocks guarantee themechanical and thermal contact between the DAQ boards and the crates.The cooling system of the front end electronics consists of a network of

(a) CAD view of the DAQ cooling sys-tem. The lines are highlighted inblue and red.

(b) Exploded CAD view of a cratewhich shows the milled coolinglines, highlighted in blue.

Figure 2.7: CAD modes of the DAQ cooling system (source: Mu2e exper-iment data center).

2.5. CALORIMETER ELECTRONICS COOLING 19

copper pipes. There are 18 straight pipes and 20 with a 180 degrees elbowfor each calorimeter disk. The pipes have an internal diameter of 3 mm andan external diameter of 4 mm. This design (Figure 2.8) has the followingadvantages:

• the cost is relatively low;

• most pipes are in thermal contact with approximately the same num-ber of front end units, therefore they approximately remove the samepower;

• it is simple to build;

• it allows to have short pipes and many of these are straight, reducingthe pressure losses.

The backplate works as support for the FEE boards and for the coolingsystem itself, as is visible in Figure 2.8a.

(a) CAD model showing three frontend units fixed to the pipe casesand the plate. A Faraday cage cov-ers two of the tree units.

(b) CAD model showing the contactbetween pipe case and the back-plate. To reduce the thermal con-tact with the plate, the mechanicalcontact between this and the pipecases is limited to small areas.

Figure 2.8: CAD model of the cooling lines (source: Mu2e experiment datacenter).

Each front end unit is jointed to two pipe cases by four screws, andthe pipe cases are fastened to the plate with several screws too. The pipecases are made of copper as well as the pipes and the supports to reducethe thermal resistance. Each pipe is connected to an input manifold and anoutput manifold by Swagelok®VCR®connectors (Figure 2.10), which arebrazed to both with an extremely careful procedure to make sure to obtaina certain quality level. Also the cooling lines are brazed to their cases witha similar procedure, using a pure silver foil 0.15 mm thick.

The cooling fluid is a 35% monopropylene glycol aqueous solution. It hasbeen chosen for its cost and for its thermal and corrosion properties: water


cannot be used because is necessary to keep the SiPMs temperature under0 ◦C. An overview of its properties is reported in Table 2.1.

Propperty Symbol Value

Density ρ 1040 kg/m3

Specific heat c 3759 J/kgKDynamic viscosity µ 4.331× 10−3 Pas

thermal conductivity k 0.429 W/mKFreezing point Tf −17 ◦C

Table 2.1: Properties of 35% monopropylene glycol aqueous solution at−10 ◦C

The fluid is provided by a chiller external to the cryostat. The hydraulicscheme of the subsystem is visible in Figure 2.11

Figure 2.9: CAD model of the front end cooling system on the backplate.The 38 pipes and the two manifolds are clearly visible (source:Mu2e experiment data center).

2.5. CALORIMETER ELECTRONICS COOLING 21

Figure 2.10: CAD model showing the connection between pipes and mani-folds, realized by Swagelok®VCR®connectors (source: Mu2eexperiment data center).

Figure 2.11: Hydraulic scheme of the front end cooling system. Forsimplicity, only two front end units have been represented(source: Mu2e experiment data center).


Chapter 3

Thermal analysis of the SiPM

In this Chapter we will report the results of the thermal simulation of theSiPM and front end units. The goal of the simulation is understanding thethermal behaviour of the electronic components at run time. The simulationhas to be as accurate as possible, since the electronic components are fullyfunctional only within a limited range of temperatures and their reliabilityand lifetime depend on the temperature of operation. Furthermore, accessto the detector for repairs or maintenance will be limited to few weeks in oneyear at run time. This means that every effort has to be made to improve thesystem reliability as much as possible. Electronic components vendors usu-ally specify the critical temperature below which the electronic componentshave to be maintained. Since the SiPM is the component most sensitiveon temperature, we mainly focused our attention on this component. Weknow that SiPM performance has a strong dependence on the operationaltemperature which will have to be maintained below 0℃. Our goal is thus todesign a system which allows to keep the SiPM temperature below 0℃ withan adequate safety factor. A preliminary analysis has already been reportedin [14] and [13].

In this Chapter we will describe the improvements to the previous studies,which include a more accurate model of the SiPM and an accurate study ofthe effect due to the distribution of the glue used to glue the SiPM to thecopper support. The Chapter is divided in three different sections: thefirst one describes the thermal simulation of one single SiPM , the secondone describes the simulation of a complete front end unit, and the last onereports our conclusions.

3.1 SiPM simulation

The SiPM adopted for the Mu2e calorimeter is custom produced by theJapanese company HamamatsuTM ([15]). The company reports a value ofthe Overall Thermal Resistance (OTR) of 4.9× 10−4 Km2/W. The (OTR)

23

24 CHAPTER 3. THERMAL ANALYSIS OF THE SIPM

is defined as ratio between the SiPM thickness (s) and the SiPM thermalconductivity (k). From the SiPM cross section (14×19.4 mm2) and thick-ness (1.35 mm), I have estimated the thermal conductivity and the thermalresistance, which are respectively ks = 2.8 W/mK and Rsipm = 1.8 K/W.

Since at the time of writing this Thesis Hamamatsu had provided onlypreliminary technical drawings (Appendix A on page 61), I have tried todevelop a model of the SiPM on the basis of this limited information toreproduce the value of the device thermal conductivity.

3.1.1 SiPM model

Figure 3.1 shows a cross section of the SiPM with a schematic representa-tion of the most relevant parts, which include the G10 support, the metal,the underfill resin and the silicon sensor. Table 3.1 on the facing page re-ports the numeric values of the thickness and thermal conductivity of all thecomponents.

(a) Back side of the SiPM . (b) Front side of the SiPM .

Metal

Silicon

G10

Underfill resin

(c) Section of the SiPM .

Figure 3.1: Schematic representation of a SiPM. a) SiPM back side withthe metal ring; b) SiPM front side with the six adjacent siliconlayers; c) main SiPM components: the sensitive silicon layer,the underfill resin layer, the G10 body and the metal contactwhich is asymmetric.

3.1. SIPM SIMULATION 25

Components Thickness Thermal Conductivity(mm) (W/mK)

G10 0.9 k⊥ = 0.3k// = 0.9

Metal 0.7 200Underfill resin 0.2 2.4

Silicon 0.15 148

Table 3.1: Thickness and thermal conductivity of the SiPM components.

Since the SiPM components are very thin the finite element analysis mayhave two problems. In order to have a reliable and numerically stable result,at least two mesh elements should be inserted in the SiPM thickness, and itis good practice to not use tiny mesh elements.

A possible solution is to multiply both the SiPM thickness and thermalconductivity in the thickness direction by the same numerical factor. Thisartificially increases the volume and allows to insert more mesh elements,but it does not change the SiPM thermal resistance. In our case we havemultiplied by a factor of two. Table 3.2 shows the new thickness and thermalconductivity values we have used in the model. As a consequence of thisprocedure, the components which were originally isotropic, the metal, theunderfill resin and the silicon, now have an anisotropic thermal conductivity.Table 3.2 shows the resulting numerical values.

Components Thickness kx ky kz(mm) (W/mK) (W/mK) (W/mK)

G10 1.8 0.9 0.9 0.6Metal 1.4 200 200 400

Underfill resin 0.4 2.4 2.4 4.8Silicon 0.30 148 148 296

Table 3.2: Thickness and thermal conductivity of the SiPM componentsimplemented in the thermal model after the rescaling.

3.1.2 Boundary condition

Figure 3.2 on the following page shows the boundary condition used in thethernal simulation. I have fixed the temperature of the back side of the SiPMat 0 ◦C. The temperature is uniform on the entire surface. The temperatureof the silicon pieces on the front side is determined from the simulation fora dissipated power of 1 W (Figure 3.2b on the next page).


(a) Constant temperature on oneface.

(b) 1W power on the silicon pieces.

Figure 3.2: Boundary condition chosen for the SiPM thermal simulation;(left) The temperature of the entire SiPM back side is fixed atthe value of 0 ◦C; (right) the temperature of the silicon pieceson the front side is determined from the simulation for a dissi-pated power of 1 W.

3.1.3 Results

Figure 3.3 on the facing page shows the SiPM temperature field determinedby the simulation. Since the SiPM internal distribution of the components isnot symmetric (Figure 3.1), also the resulting temperature field is not sym-metric. The maximum estimated temperature value on the silicon surfaceis ' 5 ◦C. As expected, the SiPM region with a larger fraction of G10 withrespect to metal has higher temperatures. We expected this effect since G10has a much lower thermal conductance than metal.

The maximum temperature value on the silicon surface estimated by thesimulation is not consistent with the estimate which can be obtained usingthe OTR value provided by Hamamatsu. If the power dissipated by theSiPM on the silicon surface is 1 W, the temperature difference ∆T betweenthe silicon surface and the G10 surface should be ∆T = 1.7 K. On the otherhand, we have estimated ∆T = 5 K. This is probably due to the limitedaccuracy of the SiPM model we have developed and to the fact we do notknow exactly how the OTR has been calculated by Hamamatsu. We can useour SiPM model to obtain conservative estimates of the temperature fieldon the silicon surface and internally to the SiPM. This is extremely usefulto determine if there are critical regions in the device.

3.2 Thermal model of the front end unit

Chapter 2 reports an accurate description of the front end unit, includingthe SiPM copper support and the electronic boards. In this Section we willdescribe the model of the front end unit used for the thermal simulation.

Previous analyses reported in [14] and [13] have shown that the tempera-ture field of the SiPM copper support is almost uniform, with a variation of

3.2. THERMAL MODEL OF THE FRONT END UNIT 27

Figure 3.3: SiPM temperature field determined by the thermal simulation.The asymmetric temperature distribution is due to the asym-metric G10 and metal distribution internal to the SiPM.


Figure 3.4: Front end electronic model.

approximately 1 degree between the upper surface, which is contact with thecooling pipes, and the lower surface of the support, on which the SiPM isglued. We can consider this as well established. In order to simplify themodel and improve the SiPM simulation by using a larger number of meshelements, I have decided to cut the SiPM support at the distance of 12 mmfrom the SiPM and fix a uniform value of the temperature at the surface ofthe support as a boundary condition of the simulation. Figure 3.4 shows thenew model I have simulated.

3.2.1 The glue

The SiPMs are glued to the copper support. We have chosen the 3MTM

Thermally Conductive Epoxy Adhesive TC-2810, that is a two-part epoxywhich contains boron nitride filler for a good thermal conductivity (approx-imately kg = 1.2 W/mK) and high adhesion ([1]). It has also a low CI ioncontent and outgassing, which is very important for vacuum application. A0.1 mm layer of glue is placed between SiPM holder and SiPM .

3.2.1.1 Glue distribution

I have used the simulation also to test two alternative glue distributionsto study the possible effects on the thermal behaviour of the assembledSiPM and support. Of course, the capability of distributing the glue withaccuracy is crucial. Figure 3.5 on the facing page shows the two alterna-tive distributions of the glue we have considered. As we have done withthe SiPM , we have artificially increased the thickness of the glue layer from0.1 mm to 0.3 mm to simplify the finite element analysis. The resultingthermal conductivity of the glue layer used in the thermal simulation iskg = 1.2× 3 = 3.6 W/mK.

3.2. THERMAL MODEL OF THE FRONT END UNIT 29

(a) Glue distribution a. (b) Glue distribution b.

Figure 3.5: Schematic representation of the two alternative glue distribu-tions on the copper support studied with the thermal simula-tion.

3.2.2 The SiPM support

We have chosen copper for the SiPM support for the copper high thermalconductivity. The support will be milled. Figure 3.6 shows a schematicrepresentation of the internal side of the support which hosts the connectionsto the front-end boards. The SiPM is glued on the hidden side.

(a) CAD of the completeSiPM support.

(b) Detail of the SiPM support used inthe simulation.

Figure 3.6: Schematic view of the internal part of the SiPM support; theSiPMs is glued to the hidden lower surface.

3.2.3 The problem of radiation from the CsI crystals

The thermal simulation of the SiPM has to include also radiation effects.First of all, we should take into account the radiation absorbed by theSiPM from the environment, in particular from the radiating CsI crystalswhich completely cover the SiPM field of view. Then, also the radiationemitted by the SiPM itself should be included.


To perform the radiation analysis we have developed a model also of theCsI crystal. The dimensions of the crystal are 34 mm×34 mm×200 mm, andthe crystal is wrapped with a layer of Tyvek®0.15 mm thick. The functionof the Tyvek® is to provide an optical insulation of each crystal from all theadjacent crystals. The scintillation light generated by the electron impactingon one crystal should not propagate to the adjacent crystals to not degradethe localization of the point of impact which is estimated from center ofmass algorithms of the deposited energy. The crystal surface facing theSiPMs is not wrapped since the light transmission from the crystal to theSiPM has to be maximum. The distance between the crystal and the SiPM isapproximately 1.5 mm. Table 3.3 reports the CsI properties relevant for thisanalysis which I have collected from a search in the literature.

Property value

CsI emissivity 0.92CsI thermal conductivity 8 W/mK

Tyvek®emissivity 0.2SiPM emissivity 0.92

Table 3.3: CsI properties needed for the radiation analysis.

3.2.4 Boundary conditions of the thermal analysis

We have performed the thermal analysis of the SiPM for the two alternativeglue distributions. In both cases the boundary condition on the temperatureof the copper SiPM support is the same.

We know the maximum expected heat flow is 0.69 W for the SiPMs placedon the most internal calorimeter ring, and the minimum is 0.23 W for theSiPMs placed on the most external rings. We have decided to perform thesimulation using the larger value of 0.69 W. This will provide a conservativeupper bound for all the SiPMs .

The boundary conditions are:

• uniform temperature of −7.4℃ on the cut surface of the copper me-chanical support;

• 0.69 W uniformly distributed on the six adjacent silicon layers of theSiPM . Since one front-end unit is made of two SiPMs , the resultingtotal dissipated power is 0.69W × 2 = 1.38 W;

• Perfect radiation surface-to-surface coupling between the two SiPMs andthe CsI crystal face;

• Radiation between the five faces of the crystal and the environment.

These are on figure 3.7 on the next page.

3.3. RESULTS 31

(a) Temperature of −7.4℃ on the freesupport surface.

(b) 0.69W dissipated power on the allsurface of the SiPM silicon piece.

(c) Radiation between the SiPM andthe crystal.

(d) Radiation from the surface of thecrystal and the environment.

Figure 3.7: Boundary conditions for the SiPM thermal simulation.

3.3 Results

The SiPM simulation we have developed determines a difference between thetemperature of the two SiPM surfaces of approximately 5 ◦C. This is largerthan the 1.7 ◦C which can be estimated from the OTR value provided byHamamatsuTM. Since we have no information relative to the model used byHamamatsuTM, we cannot remove the discrepancy with our estimates, whichprovide a conservative upper bound. The important information we obtainfrom the simulation is the temperature field on the SiPM silicon surfacewhich shows that the temperature is not uniform and that it significantlydepends on the glue distribution (Figure 3.9 on page 33). The differencebetween the maximum temperature of the silicon surface estimated for thetwo glue distributions is of the order of 2.5 ◦C.Figure 3.9 on page 33 alsoshows that only type b allows to keep all the silicon surface temperaturebelow 0℃.


Figure 3.8: SiPM temperature with glue distribution type a.

3.3. RESULTS 33

Figure 3.9: SiPM temperature with glue distribution type b.


Chapter 4

PEEK tensile and gluing tests

In this Chapter we will describe the mechanical tests performed to verify ifPEEK (the acronym for PolyEther Ether Ketone) is adequate to fabricatethe backplate which supports all the front-end units of one calorimeter disk(Figure 4.1).

Figure 4.1: Schematic CAD representation of the backplate of onecalorimeter disk.

We have performed two kinds of tests: a tensile test to verify PEEKstatic strength, and a test of the glue bonding PEEK-PEEK to quantify theadequacy of the commercially available adhesives. Given the dimensions,outer diameter of 1430 mm, inner hole diameter of 672 mm, and thicknessof 15 mm, we know very few companies could machine the backplate in onesingle piece and the process would be expensive. The gluing tests are thenimportant since it will probably be necessary to fabricate the backplate inseveral pieces glued together. The backplate also has to be accurately ma-chined. All around the external perimeter and the inner hole, several holeshave to be prepared to bolt the disk respectively to the inner and to theouter ring of the calorimeter. Also, the slots to house the cooling pipes have

35

36 CHAPTER 4. PEEK TENSILE AND GLUING TESTS

to be milled in the plate. Several hundreds of M2 holes are also requiredto fix the cooling lines, in addition to other holes necessary for the opticalfibers and other features. There are also 674 rectangular holes per disk toinsert the SiPMs supports.

4.1 PEEK

PEEK is a particular thermoplastic polymer with high performance and cost.We have tested Ketron®1000 which is produced by Quadrant (technicaldatasheet is on the annex B on page 67). We have chosen Ketron®1000 forthe following properties [16]:

• low thermal conductivity (0.25 W/mK); this means that an extremelylimited amount of power can be transferred from the backplate to thecooling fluid by conduction;

• good mechanical strength and stiffness; this means that the plate willhave limited distortions;

• it can be easily machined;

• limited outgassing rate, which is crucial for operation in vacuum;

• it can be used in a 1 T magnetic field.

4.2 Testing machine

Figure 4.2 on the next page shows the testing machine we have used. It is pro-duced by Lloyd Instruments, series LR50KPlus. The standard LR50KPlusfeatures a twin column design with a maximum crosshead travel with anextension resolution < 0.05µm ([2]).

4.2.1 Load cell and grips

The load cell and the grips are also made by Lloyd Instruments. The loadcell is a 50 kN with an accuracy of 0.5% which corresponds to 250 N.

The grips are V shaped. This means that as the specimen is stretched, thecontact pressure between the specimen and the grips increases. This preventsthe holding part of the specimen from sliding, which is very important in thetensile test.

4.3 Tensile tests

The tensile tests have been performed to verify the PEEK mechanical prop-erties. We have tested five specimens to check also data can be reproduced.

4.3. TENSILE TESTS 37

Figure 4.2: Testing machine (Lloyd Instruments, series LR50KPlus).

(a) Load cell. (b) Grips.

Figure 4.3: Testing machine accessories.


The data was normalized with the cross section area A = 13× 5 = 65 mm2

and an equivalent length of l∗ ' 105 mm. l∗ was found considering thescheme in Figure 4.4, where the specimen is approx with one with two sec-tion without fillet, where:

• L1 = 115 mm is the distance between the grips;

• L2 = 73 mm is an average distance between the R76 fillet begin andend;

• D1 = 19 mm and D2 = 13 mm are the two specimen dimensions

• the thickness is s = 5 mm and it is not indicated in Figure 4.4.

Figure 4.4: Simple specimen used to define an equivalent length.

For the beam theory, considering the specimen in Figure 4.4

∆L =N

E

(L1 − L2

sD1+

L2

sD2

).

It must be the same as

∆L =Nl∗

EsD1.

By the previous formula

l∗ =(L1 − L2

sD1+

L2

sD2

)sD1 ' 105 mm.

The test speed was set at 5 mm/min, that means a strain rate ε =800µε/s. That means a quasi-static loading.

The information about the test methods and interpretation of the resultshas been taken from the literature [11], [5], [4].


4.3.1 Preparation of the PEEK specimens

All PEEK specimens have been milled by a CNC (computer numerical con-trol) machine. The technical drawings have been reported in Chapter A onpage 61. The dimensions follow the Type I described in the standard ASTM638 [11]. Figure 4.5 shows the precision measurement of the specimen trans-verse dimensions using a caliper. In the Table 4.1 the are the measure of thecross section of the all specimens.

(a) Specimen width. (b) Specimen thickness.

Figure 4.5: Measurement of the PEEK specimen transverse dimensions.

Specimen s D1

(mm) (mm)

2 4.96 12.953 4.97 12.994 4.94 12.955 4.92 12.956 4.92 12.95

Table 4.1: Measure of the tensile specimen cross section.

4.3.2 Results

Figure 4.6a on the following page shows the force-displacement diagram ob-tained from the tests of the five specimens. Figure 4.6b on the next pageshows the specimens after the tests. Table 4.2 on page 42 reports the valuesof all the ultimate tensile strengths σu, evalueted with the maximum force.Using the value of A = 65 mm2 and l∗ = 105 mm it is possible to find thestress strain diagram, Figure 4.7 on page 41 for the material PEEK. It isalso possible to estimate the value of the Young’s modulus E.


(a) Force displacement diagram.

(b) Broken specimens after tensile test.

Figure 4.6: Photograph of the five specimes after the tensile test.


Figure 4.7: Stress strain diagram for PEEK


Specimen n° Max Force σu E(N) (MPa) (MPa)

2 6843 105.3 42103 6798 104.6 40804 6799 104.6 42605 6803 104.7 42606 6880 105.8 3950

Table 4.2: Maximum force, ultimate tensile strengths and Young’s modulusfor the five specimens.

4.4 Stepped joint

The number of companies which can machine the backplate in one piece islimited and the process expensive. An alternative to increase the number ofpossible companies and reduce the fabrication cost is building the backplatefrom separate parts. There are two alternative ways to joint the parts ofthe backplate together: by welding or by gluing. The literature reportslimited documentation relative to PEEK gluing. We know PEEK is difficultto glue because of its low wetting. We have tested three different adhesive todeterminate their strength. For each adhesive we have made two specimens.

We chose a speed test of 3 mm/min to increase the average stress of theadhesive to the level of approximately 8.3 ÷ 9.7 MPa/min. That means astrain rate of ε = 3

240×60 ' 210µε/s.By the beam theory

∆l =Nl

EA.

We can consider that the elongation of the all specimens is given by thePEEK only. In our case the specimen has two different cross sections, so,considering the scheme of Figure 4.8,

L1 L2

A = Gluing areai

A 1

A 2

Figure 4.8: Scheme of the step joint used for determinate the speed test.

4.4. STEPPED JOINT 43

∆l =N

E

( l1A1

+l2A2

).

The average stress in the adhesive is NAi, so

∆l =N

AiE

( l1A1

+l2A2

)Ai

where NAi

= 8.3 ÷ 9.7 MPa, E = 4300 MPa, l1 = 100 mm, l2 = 50 mm,A1 = 510 mm2, A2 = 225 mm2 and Ai = 1500 mm2. To find the machinespeed we have to multiply ∆l times two because the specimen is made bytwo step parts. N

Aiis really per minute unite, so ∆l obtained also per minute

unite.The test methods and the terminology used in this Thesis are based on

the ASTM standards [12], [7], [8], [9], [10] and the adhesive vendor informa-tion.

4.4.1 Tested adhesives

Three epoxy bicomponent adhesives have been tested, DP490 and 3M 2216produced by 3M [1], Araldite 2011 produced by Araldite [3]. The goal ofthis test is determine which adhesive has the best performance.

DP 490

3M Scotch-Weld Epoxy Adhesive 490 is a black, thixotropic, gap-filling two-component epoxy adhesive with particularly good application characteristics.It is designed for cases which require ultimate toughness and high strength.DP490 shows good adhesion to many plastic surfaces even by simply solventwiping. For more details the datasheet is reported at chapter B on page 67.

Araldite 2011

Araldite 2011 is a multipurpose, two-component, room temperature curing,paste adhesive of high strength and toughness. It is suitable for a wide vari-ety of metals, ceramics, glass, rubber, rigid plastics and most other materialsof common use. It is a versatile adhesive for the craftsman as well as mostindustrial applications and it has a very short cure time. It has a shear mod-ulus of approximately 0.8 GPa. For more details the datasheet is reportedat chapter B on page 67.

3M 2216

3M Scotch-Weld Epoxy Adhesive 2216 B/A is a flexible, two-part, room tem-perature curing epoxy with high peel and shear strength. Scotch-Weld epoxy


adhesive EC-2216 B/A has been labeled, packaged, tested, and certified foraircraft and aerospace applications. It has a shear modulus of approximately342 MPa. It is a low modulus adhesive. For more details the datasheet isreported at chapter B on page 67. It has a low outgassing rate which isextremely important for application in Mu2e.

4.4.2 Preparation of the specimen

The specimen is not the single lap joint defined by most standards, but ismade of two stepped parts. The technical drawing is reported at chapter Aon page 61. This is because the possible joint designed for the backplate isa stepped one, so we would like to test this kind of joint. With a step jointit is possible to control the adhesive thickness from the tolerance of the twosteps. In our case, we chose an adhesive nominal thickness of 0.1 mm. Itis also possible to load the glued region with a uniform pressure during thecure by putting a weight on it. Anyway the size of the overlap has beenchosen following the information of the ASTM [9].

At the top and bottom of the specimen there is a little piece with a lowerthickness, 2 mm less. This is where the grips clutch the specimen. It doesnot influence the test.

4.4.2.1 Joint preparation

In the following we will describe all the aspects and steps we have followedto prepare the joint.

Specimen surface preparation

The preparation of the specimen requires the following steps:

• clean up the surface with 90° alcohol;

• use sandpaper 80 to achieve an appropriate surface roughness. Thesandpaper was used perpendicularly to the specimen longitudinal axis;

• measure the Ra and check if it is in the range 3.2÷ 6.3µm.

• clean up again the surface with 90° alcohol.

The surface roughness has been measured with a profilometer. We haveused the profilometer Mitutoyo sj 211 (Figure 4.9 on the next page). Table4.3 on the facing page reports the values of the roughness measured in twodifferent positions of the bonding area.

4.4. STEPPED JOINT 45

Figure 4.9: Roughness measurement with a profilometer.

n° Ra Ra n° Ra Ra

(µm) (µm) (µm) (µm)

1 3.3 2.86 4 4.16 4.21• 4.26 3.8 4• 3.6 4.52 3.57 4.57 5 3.22 3.862• 3.21 3.28 5• 4.33 5.893 4.38 3.53 6 3.345 4.383• 3.5 4.32 6• 3.31 3.67

Table 4.3: Measured values of the roughness of the overlap length.


Adhesive application

Two types of application were performed: for Araldite we used the glue gun(Figure 4.10a), for the other two 3M adhesives the two components weremixed in the right ratio and then the mixture was applied to both surfaces(Figure 4.10). The two adhesive leftover mixtures were used as proof of the

(a) Application of Araldite with a gluegun.

(b) Application of the two componentsmix for the two 3M adhesives.

Figure 4.10: Adhesive application.

glue cure.

Room conditions and days of cure

All the three adhesives cured for fourteen days into an INFN room withan approximately constant temperature of 20℃. We put a mass over eachoverlap length to have a uniform pressure over the bond area during the cure(Figure 4.11).

Figure 4.11: Specimen cure.

4.5. DOUBLE SCARF JOINT 47

4.4.3 Results

Table 4.4 reports the values of the force applied to the specimen to breakthe adhesive. Table 4.4 reports also the values of the average stress appliedto the adhesive.

Specimen n° Adhesive Force Average stress(N) (MPa)

1 DP 490 2277 1.522 DP 490 1934 1.293 Araldite 2011 2863 1.914 Araldite 2011 2399 1.605 3M 2216 3434 2.296 3M 2216 3555 2.37

Table 4.4: Results of the adhesive step joint test.

This kind of joint can not support high force because in the step corneris a singularity, so the stress value is infinity.

4.5 Double scarf joint

We tested also a double scarf joint to make a comparison with the steppedone. We decided to test this kind of joint because of its short bonded length.Two different adhesive thicknesses were tested and two specimens were madefor each thickness.

The design angle of the double scarf is 90° because it can be easily ob-tained by milling. Different angles would need a dedicated tool. The tech-nical drawings of the two half specimens are reported in the annex A.

Only the 3M 2216 adhesive was tested because it is the one that hadbetter results with the stepped joint.

4.5.1 Test of the adhesive thickness

Two adhesive thickness were tested:

• Zero Line Thickness (ZLT): the two half specimen were put one againstthe other without anything in the middle;

• 0.12 mm: fishing line was used to determinate the thickness (Fig-ure 4.12 on the following page). Two pieces of fishing line were used toavoid relative rotation of the two half specimens. The line will remaininto the adhesive.


Figure 4.12: Fishing line used to perform the test of the adhesive thickness.

4.5.2 Joint preparation

In the following we will describe all the aspects and steps we have followedto prepare the joint.

Specimen surface preparation

The preparation of the specimen followed the same steps followed for thestepped joint, that is cleaning up the surface with alcohol, use sandpaper80 and clean them up again. The joint has two faces, so we measured theroughness on both sides. The values of the roughness are reported in Ta-ble 4.5 on the next page. We used the letter F for the concave one and theletter M for the other (the convex one) and we used U for the up side or Dfor the down side (it was signed a top side of each half specimen).

Room condition and days of cure

The specimens cured for 14 days in the INFN clean room. There was a pre-vious try of bonding without success because of the humidity, so we decidedto avoid this problem for the test. We put the specimens over a table witha face against a wall and then an heavy mass on the other face (Figure 4.13on the facing page). There was also a tissue between the specimens and themass.

4.5. DOUBLE SCARF JOINT 49

n° Ra n° Ra

(µm) (µm)

1 F U 3.17 3 F U 5.001 F D 4.73 3 F D 4.121 M U 3.17 3 M U 5.721 M D 4.34 3 M D 4.592 F U 3.96 4 F U 3.412 F D 5.71 4 F D 3.522 M U 3.63 4 M U 4.402 M D 5.09 4 M D 4.94

Table 4.5: Measured values of the roughness of both sides of the doublescarf joint.

Figure 4.13: Cure of the double scarf specimens.


4.5.3 Results

The average values of the stress component σ and τ on the adhesive, Fig-ure 4.14 are

σ = τ =F

2A

where A = 17 × 30 = 510 mm2 is the value of cross sectio of the specimenand F is the value of the force given by the test machine.

σ

τ

A

Figure 4.14: Adhesive stress components.

Table 4.6 reports the values of the force and the τ stress componentapplied to the specimen to break the adhesive.

Specimen n° Thickness Force τ(mm) (N) (MPa)

1 0.12 5153 5.02 0.12 3346 3.33 ZLT 3200 3.14 ZLT 3323 3.2

Table 4.6: Results of the adhesive double scarf joint test.

4.6 Conclusions

Tensile test

All the values of the ultimate tensile strength have a very low dispersion.The average value of the five tests σua = 105 MPa follows the Quadrantdata.

The diagram shows that after the ultimate strength the value of the forceis approximately constant. A reasonable stress design value for the PEEKstrength should be σamm = 5200

5×13 = 80 MPa, that is the constant force valueper initial specimen cross area.

4.6. CONCLUSIONS 51

Adhesive bonding tests

The adhesive that can support the most intense force is the low modulusadhesive 3M 2216. According to the theory, in the corner where the twohalves match in this kind of joint the adhesive stress should be infinite. Sothe more rigid the adhesive is, the higher is the stress, and it is going to havea brittle fracture. A low modulus adhesive allows to redistribute the stressin all the bonded area.

With the double scarf joint the glue can support a higher force but thereare also some problems:

• it is difficult to apply a uniform pressure during the cure, especially inbig parts;

• the backplate does not have to support high load, so it is not necessarythe strongest joint;

• the coupling is less accurate then in the step one, and this is morerelevant than the strength of the joint.

So in case we will have to glue the backplate, we will use a step jointwith the 3M 2216 adhesive. Figure 4.15 reports several photographs of theperformed tests.


(a) Tensile specimen bro-ken on machine.

(b) Adhesive specimenmounted on machine.

(c) Broken step specimens. (d) Broken double scarf specimens.

Figure 4.15: Pictures of the samples and tools used to perform the tests.

Chapter 5

Thermal deformation studies

In this chapter we will report a preliminary study of the design precautionsnecessary to take into account the thermal deformations of the front-endcopper cooling lines. These deformations take place at run time with thedecrease of the cooling fluid temperature from room temperature (20 ◦C) tothe operational temperature (−10 ◦C). Figure 5.1 shows the CAD repre-sentation of the entire PEEK backplate (Figure 5.1 a) and a detail of thecooling lines (Figure 5.1 b), with the holes for the M2 tap-bolt which fixthe cooling lines to the backplate. An example is reported in Figure 5.2on the following page. Since the backplate design has been developed tominimize the thermal contact between the backplate itself and the coolinglines, at run time the cooling lines and the backplate will have a differenttemperature. This will increase the problem due to the PEEK and copperdifferent thermal deformations which may generate tensions and distortionsof the cooling lines.

(a) Backplate with the cooling lines. (b) Detail of the cooling lines.

Figure 5.1: Schematic CAD representation of the backplate and coolinglines.

5.1 The problem

The cooling fluid operational temperature is −10 ◦C. This means that thefluid temperature will be reduced by the chiller from room temperature

53

54 CHAPTER 5. THERMAL DEFORMATION STUDIES

Figure 5.2: Examples of M2 tap-bolt inserted in a PEEK sample.

(20 ◦C) to −10 ◦C at run time. There will be a thermal contraction of thecopper cooling lines. It is straightforward to estimate that the contraction ofa 1 m long copper line is of the order of 0.5 mm for a temperature variationof 30 ◦C. On the other hand, given the limited thermal coupling between thebackplate and the cooling lines, the variation of the backplate temperaturewill be more limited. In addition, PEEK has a much lower coefficient ofthermal expansion than copper. This will result in a different thermal defor-mation of the cooling lines, which may be significant, and of the backplate,which will be minimal and will be neglected in the following study. Thebackplate design has to minimize the mechanical contact between the head’sbolt and the cooling lines to allow a free contraction and expansion of thecooling lines (Figure 5.3).

free play

cooling lines

PEEK

tap bolt

Figure 5.3: M2 tap-bolt on PEEK

5.2. PRELIMINARY MODEL 55

5.2 Preliminary model

For this preliminary study we have used the following simple model:

• there is no friction between the cooling lines and backplate;

• there is no heat exchange between the cooling lines and backplate;

• the cooling lines have only a longitudinal contraction.

In case friction is negligible, the contraction ∆l of the cooling line is givenby the formula:

∆l = α×∆T × l

where α is the thermal expansion coefficient, ∆T is the temperature varia-tion and l is the cooling line length. The thermal expansion coefficient ofcopper is α = 17× 10−6 K−1. In case friction is not negligible, this esti-mate of ∆l provides an upper bound. Although neglecting friction effectsmay be a simplistic hypothesis, the following two elements should be takeninto account: the friction coefficient between PEEK and copper is approxi-mately 0.35 and the tightening torque used for all the tap-bolts (plastic M2)is approximately 0.15 Nm. This implies the resulting normal force is lowand thus the friction force is limited as well. Moreover, since copper "free"contraction (i.e. in the absence of friction) provides the maximum possiblevariation of the cooling lines length, neglecting friction effects in the designis a conservative hypothesis.

For this study we have taken into account only the longitudinal contrac-tion of the cooling lines because the diameter of the pipes is negligible withrespect to their length. This implies the longitudinal direction is the onlyone with a non-negligible thermal deformation.

5.2.1 Two types of cooling lines

There are two types of cooling lines: one that goes straight between thetwo sides of the backplate and the other one is U-shaped and is used nextto the central hole. The U-shaped lines have one free corner (Figure 5.1on page 53). Since the copper pipe has the outer diameter of 4 mm andthe inner diameter of 3 mm, it has a very low stiffness and it can adjustany mismatch between the two parts. This means the two U segments canbe considered as independent for the thermal deformation and will simplyadjust independently.

We can focus only on the longest cooling lines which will have a non-negligible thermal deformation and are fixed to the collector on both sides.All the other holes are going to be the same.


5.3 Preliminary design solution

In order to refer the position of the cooling lines to the backplate at leastone cylindrical coupling is necessary. The employed mechanical constrainthas also to be isostatic to avoid a thermal stress.

We have decided to place one spring pin at the center of the cooling lineand one in a loop at one end of the cooling line (Figure 5.4). This constrainsthe position of the cooling line center and minimizes the tension and stressdue to the thermal contraction.

Figure 5.4: Cooling line with one spring pin hole at the center and oneloop on one side.

We have decided to use a spring pin because plastic does not allow toachieve a strict tolerance, so it is not possible to have an accurate coupling.In this way the spring pin minimizes all the play with the holes. The pinhas to be made by austenitic stainless steel not to be ferromagnetic becausethe detector operates in a 1 T magnetic field.

The spring positioned at the center of the cooling lines provides alsoanother advantage: the thermal contraction of the cooling line is half on oneside and half on the other one and this reduces the free play between thebolt and copper by a factor of two.

5.3.1 Free play

The thermal deformation of the longest cooling line (1080 mm) for a tem-perature variation of 30 ◦C is approximately

∆l =17× 10−6 × 1080× 30

2= 0.3 mm

We have decided to use M2 screws produced by Bossard ([6]) to fix thecooling lines to the backplate. The screw datasheet reported in Appendix Bon page 67 shows that the head diameter of the screw is 4 mm. The diameterof the hole made through the cooling line should be at least 0.6 mm largerthan the diameter of the screw to allow a deformation of 0.3 mm of thecooling line in both directions.

5.4. CONCLUSIONS 57

5.3.2 Layout constraint

A conservative solution is to make a hole with a diameter bigger than 4.6 mm,but there is not sufficient space for a bigger hole. There is the central coolingpipe and the holes need an appropriate distance from the free edge. Since0.3 mm is a conservative choice we have chosen a diameter of 4.8 mm for thebolt head.

5.4 Conclusions

Figure 5.5 reports the design of the cooling lines, with a central spring pinand a loop. We have chosen a diameter of the bolt holes of 4.8 mm.

Figure 5.5: Design of the cooling line with a central spring pin and a lateralloop.


Chapter 6

Conclusion

The goal of the Mu2e experiment is searching for the coherent conversionof the muon to electron in the field of an atomic nucleus, a physics processwhich would prove the existence of Physics beyond the Standard Model. Thebeginning of Mu2e data taking is expected in the year 2021. The electro-magnetic calorimeter plays a crucial role in reducing the level of undesiredbackgrounds which may mimic a physics signal. It has been designed and willbe constructed by a collaboration of physicists and engineers of the IstitutoNazionale di Fisica Nucleare (INFN), the California Institute of Technology(CalTech) and Fermilab (FNAL).

I have participated in several aspects of the Mu2e calorimeter mechani-cal design. I have developed a detailed SiPM thermal model to estimate thetemperature distribution through its components. The SiPMs play a cru-cial role in the Mu2e calorimeter because they convert the light producedby scintillation in the crystals into electrical signals which are digitized andacquired. The thermal analysis of the SiPMs is very important becausethe SiPMs performance strongly depends on their temperature. The ther-mal analysis has been necessary also to choose between alternative distribu-tions of the thermal conductivity glue used to fix the SiPM to the copperSiPM holder.

The second part of my work has been the study of the glue bonding ofa PEEK-PEEK joint. This has been necessary because at the moment it isnot sure if it will be possible to make the calorimeter backplate in a singlepiece of PEEK. I performed a tensile test to verify if PEEK mechanicalproperties are compatible with the technical specifications given by Quadrant(the producer). This test was performed by following ASTM standards. Ialso tested three different adhesive good for plastic substrate and for vacuumto choose the best one. Two specimens for each adhesive were tested. Thejoint was a step one because this is the joint designed for the glued backplate.Then I also tested a double scarf joint with a 90° angle. The tested adhesivewas the best one I could find with the step joint test. In this case two different

59

60 CHAPTER 6. CONCLUSION

adhesive thicknesses were tested with two specimens for each thickness. Thedouble scarf joint was tested as an R&D (it is common to use PEEK becauseof its outgassing properties) for INFN to determine how strong this kind ofjoint is.

The last part of my work has been a preliminary study of the thermalcontraction of the front end cooling lines at run-time. The cooling linesare made of copper and are fixed with several M2 tap bolts to the PEEKbackplate. The temperature of the cooling lines at running time is −10 ◦C.The goal of this study has been finding an isostatic position reference forthe cooling lines to avoid the contact between the M2 holes on them and thecorresponding bolts during the thermal contraction.

I also spent one week at Fermilab to discuss the results of my work withmy Fermilab colleaugues at the Mu2e Collaboration Meeting (June 2018).

Appendix A

Technical drawings

61

PIN

No.

12

34

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)[s

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(1-A)

Cat

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)[s

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Cat

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)[s

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Anode

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1 1

2 2

3 3

4 4

5 5

6 6

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CC

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Eugenio

13/02/2018

Designed by

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Approved by

Date

1 / 1

Edition

Sheet

Date

165

7

6

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-

1

1

+

50,0

-0,5

0,5

+

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1 1

2 2

3 3

4 4

5 5

6 6

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CC

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ProvinoIncollaggio

Eugenio

20/03/2018

Designed by

Checked by

Approved by

Date

1 / 1

Edition

Sheet

Date

15

150

30

50

7,50

-0,05

0,00+

PEEK

N° 12 PRO

VIN

I

17

30

1 1

2 2

3 3

4 4

5 5

6 6

AA

BB

CC

DD

ProvinoIncollaggio_scarf1

Eugenio

04/05/2018

Designed by

Checked by

Approved by

Date

1 / 1

Edition

Sheet

Date

120

90°

8,50

N° 4 PRO

VIN

I

15

17

30

120

1 1

2 2

3 3

4 4

5 5

6 6

AA

BB

CC

DD

ProvinoIncollaggio_scarf2

Eugenio

04/05/2018

Designed by

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Approved by

Date

1 / 1

Edition

Sheet

Date

120

90°

8,50

15

17

30

N° 4 PRO

VIN

I

Appendix B

Datasheet

67

>> POLYETHERETHERKETONE [PEEK]

Physical properties (indicative values g)PROPERTIES Test methods Units VALUES

Colour - - natural (brownish

grey) / black

Density ISO 1183-1 g/cm³ 1.31

Water absorption:

- after 24/96 h immersion in water of 23 °C (1) ISO 62 mg 5 / 10

ISO 62 % 0.06 / 0.12

- at saturation in air of 23 °C / 50 % RH - % 0.20

- at saturation in water of 23 °C - % 0.45

Thermal Properties (2)

Melting temperature (DSC, 10 °C/min) ISO 11357-1/-3 °C 340

Glass transition temperature (DSC, 20 °C/min) - (3) ISO 11357-1/-2 °C -

Thermal conductivity at 23 °C - W/(K.m) 0.25

Coefficient of linear thermal expansion:

- average value between 23 and 100 °C - m/(m.K) 50 x 10-6

- average value between 23 and 150 °C - m/(m.K) 55 x 10-6

- average value above 150 °C - m/(m.K) 130 x 10-6

Temperature of deflection under load:

- method A: 1.8 MPa ISO 75-1/-2 °C 160

Max. allowable service temperature in air:

- for short periods (4) - °C 310

- continuously : for min. 20,000 h (5) - °C 250

Min. service temperature (6) - °C -50

Flammability (7):

- "Oxygen Index" ISO 4589-1/-2 % 35

- according to UL 94 (1.5 / 3 mm thickness) - - V-0 / V-0

Mechanical Properties at 23 °C (8) 0 0

Tension test (9):

- tensile stress at yield / tensile stress at break (10) ISO 527-1/-2 MPa 115 / -

- tensile strength (10) ISO 527-1/-2 MPa 115

- tensile strain at yield(10) ISO 527-1/-2 % 5

- tensile strain at break (10) ISO 527-1/-2 % 17

- tensile modulus of elasticity (11) ISO 527-1/-2 MPa 4300

Compression test (12):

- compressive stress at 1 / 2 / 5 % nominal strain (11) ISO 604 MPa 38 / 75 / 140

Charpy impact strength - unnotched (13) ISO 179-1/1eU kJ/m² no break

Charpy impact strength - notched ISO 179-1/1eA kJ/m² 3.5

Ball indentation hardness (14) ISO 2039-1 N/mm² 210

Rockwell hardness (14) ISO 2039-2 - M 105

Electrical Properties at 23 °C 0 0

Electric strength (15) IEC 60243-1 kV/mm 24

Volume resistivity IEC 60093 Ohm.cm > 10 14

Surface resistivity ANSI/ESD STM 11.11 Ohm/sq. > 10 13

Relative permittivity εr : - at 100 Hz IEC 60250 - 3.2

Relative permittivity εr : - at 1 MHz IEC 60250 - 3.2

Dielectric dissipation factor tan δ: - at 100 Hz IEC 60250 - 0.001

Dielectric dissipation factor tan δ: - at 1 MHz IEC 60250 - 0.002

Comparative tracking index (CTI) IEC 60112 - 150

Note: 1 g/cm³ = 1,000 kg/m³ ; 1 MPa = 1 N/mm² ; 1 kV/mm = 1 MV/m.

Ketron ® is a registered trademark of the Quadrant Group .

Quadrant Engineering Plastic Products global leader in engineering plastics for machining

www.quadrantplastics.com

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25, 2

014

Ketron® 1000 PEEK

PR

OD

UC

T D

AT

A S

HE

ET

T Ketron 1000 PEEK stock shapes are produced from virgin polyetheretherketone resin and offer the highesttoughness and impact strength of all Ketron PEEK grades. Both Ketron 1000 PEEK natural & black can be sterilisedby all conventional sterilisation methods (steam, dry heat, ethylene oxide and gamma irradiation).

This product data sheet and any data and specifications presented on our website shall provide promotional and general information about the Engineering Plastic Products (the "Products")manufactured and offered by Quadrant Engineering Plastic Products ("Quadrant") and shall serve as a preliminary guide. All data and descriptions relating to the Products are of an indicativenature only. Neither this data sheet nor any data and specifications presented on our website shall create or be implied to create any legal or contractual obligation.

Any illustration of the possible fields of application of the Products shall merely demonstrate the potential of these Products, but any such description does not constitute any kind of covenantwhatsoever. Irrespective of any tests that Quadrant may have carried out with respect to any Product, Quadrant does not possess expertise in evaluating the suitability of its materials orProducts for use in specific applications or products manufactured or offered by the customer respectively. The choice of the most suitable plastics material depends on available chemicalresistance data and practical experience, but often preliminary testing of the finished plastics part under actual service conditions (right chemical, concentration, temperature and contact time,as well as other conditions) is required to assess its final suitability for the given application.

It thus remains the customer's sole responsibility to test and assess the suitability and compatibility of Quadrant's Products for its intended applications, processes and uses, and to choosethose Products which according to its assessment meet the requirements applicable to the specific use of the finished product. The customer undertakes all liability in respect of the ap-plication, processing or use of the aforementioned information or product, or any consequence thereof, and shall verify its quality and other properties.

Legend:

(1) According to method 1 of ISO 62 and done on discs Ø 50 mm x 3 mm.

(2) The figures given for these properties are for the most part derived from raw material supplier data and other publications.

(3) Values for this property are only given here for amorphous materials and for materials that do not show a melting temperature (PBI & PI).

(4) Only for short time exposure (a few hours) in applications where no or only a very low load is applied to the material.

(5) Temperature resistance over a period of min. 20,000 hours. After this period of time, there is a decrease in tensile strength –measured at 23 °C – of about 50 % as compared with the original value.

The temperature value given here is thus based on the thermal-oxidative degradation which takes place and causes a reduction in properties. Note, however, that the maximum allowable service temperature depends in many cases essentially on the duration and the magnitude of the mechanical stresses to which the material is subjected.

(6) Impact strength decreasing with decreasing temperature, the minimum allowable service temperature is practically mainly determined by the extent to which the material is subjected to impact. The value given here is based on unfavourable impact conditions and may consequently not be considered as being the absolute practical limit.

(7) These estimated ratings, derived from raw material supplier data and other publications, are not intended to reflect hazards presented by the material under actual fire conditions. There is no ‘UL File Number’ available for Ketron 1000 PEEK stock shapes.

(8) Most of the figures given for the mechanical properties are average values of tests run on test specimens machined out of rod Ø 40 - 60 mm. Except for the hardness tests, the test specimens were then taken from an area mid between centre and outside diameter, with their length in longitudinal direction (parallel to the extrusion direction).

(9) Test specimens: Type 1 B (10) Test speed: 50 mm/min [chosen acc. to ISO 10350-1 as a function

of the ductile behaviour of the material (tough or brittle)] (11) Test speed: 1 mm/min. (12) Test specimens: cylinders Ø 8 mm x 16 mm (13) Pendulum used: 4 J. (14) Measured on 10 mm thick test specimens (discs), mid between

centre and outside diameter.

(15) Electrode configuration: ∅ 25 mm / ∅ 75 mm coaxial cylinders ; in transformer oil according to IEC 60296 ; 1 mm thick test specimens.

g This table, mainly to be used for comparison purposes, is a

valuable help in the choice of a material. The data listed here fall within the normal range of product properties. However, they are not guaranteed and they should not be used to establish material specification limits nor used alone as the basis of design.

Scotch-Weld

EPX Adhesive DP490

Product Data SheetUpdated : March 1996Supersedes : November 1993

Product Description DP490 is a black,thixotropic, gap filling twocomponent epoxy adhesivewith particularly goodapplication characteristics.

It is designed for use wheretoughness and high strengthare required and showsspecial benefits in theconstruction of compositeassemblies.

The product has excellentheat and environmentalresistance.

Physical PropertiesNot for specification purposes

BASE ACCELERATOR

Specific Gravity 1.00 1.00

Consistency Non-sag paste Non-sag paste

Mix Ratio By WeightBy Volume

100100

5050

Colour Black Off-White

Work Life 1.5 hours minimum at 23°C

Time to HandlingStrength

4 to 6 hours at 23°C

Time to Full Strength 7 days (test to full performance at one week)

Shelf Life 15 months from date of despatch by 3M when stored in theoriginal carton at 21°C (70°F) & 50 % Relative Humidity

PerformanceCharacteristicsNot for specification purposes

PerformanceCharacteristics of theCured Adhesive.

Two cure cycles wereevaluated as follows:

Cure Cycle 1 7 days at 23°C

Cure Cycle 2 24 hours at 23°C, 1 hour at80°C

2

Date : March 1996EPX Adhesive DP490

PerformanceCharacteristics (Cont...)Not for specification purposes

TemperaturePerformance in Shearand Peel.

(Etched Aluminium) ShearStrength to BS 5350 C5,Peel Strength was floatingroller peel to BS5350 C9.

Tests were performed at23°C unless otherwisestated.

Temperature (°C) Shear Strength (1)(N/mm²)

Shear Strength (2)(N/mm²)

Peel StrengthDaN/cm

-552380

120150

23.730.211.92.81.9

31.628.712.73.21.7

N/A9.247.32N/AN/A

Adhesion to EtchedAluminium afterEnvironmental Ageing

Ageing Condition Shear Strength(N/mm²)

RT ControlWater at 23°C, 750 hours50°C, 96% RH, 750 hours120°C, 750 hours175°C, dry heat, 120 hoursSkydroll 500B at 23°C, 750 hoursJP4 at 23°C, 750 hoursHydraulic Oil at 23°C, 750 hours

26.225.622.025.329.627.628.729.5

DP490 shows goodadhesion to many plasticsurfaces even by simplysolvent wiping.

This can be improved stillfurther by the use of 3MScotchbrite abrasion and/oruse of the primer Scotch-Weld 3901.

Plastics Shear Strength(N/mm²)

Carbon Fibre Reinforced EpoxyPolyester Sheet Moulding CompoundGlass Fibre Reinforced PhenolicABS (filled)PVC (filled)Azloy (glass filled polycarbonate)Valox (glass filled PET)PMMANoryl (tm XTRA) (glass filled PPO)

36.1 (cohesive)4.3 (substrate)30.3 (cohesive)3.2 (substrate)2.9 (substrate)3.0 (adhesion)1.4 (substrate)3.7 (adhesion)4.9 (adhesion)

3


Storage Conditions Store product at 15°C to25°C for maximum storagelife.

Directions for Use/Clean Up

Place the cartridge into the3M EPX Applicator and clipinto position.

Remove the resealable cap.

Expel a small quantity ofadhesive and ensure bothcomponents flow freely.

Attach correct mixer nozzle(this should have 20 ormore elements).

Dispense the adhesive asrequired.

When finished either leavethe nozzle in place andstore, or remove the nozzle,wipe clean the tip, andreplace cap.

To re-start after storageremove the old nozzle withcured adhesive and re-fit anew nozzle, or remove thecap and fit a new nozzle.

Surface Preparation:The degree of surfacepreparation depends on thebond strength required andthe environment likely to beencountered by the bondedstructure. For most plasticssolvent wiping with 3M VHBsurface cleaner, followed byabrasion with 3MScotchbrite 7447, followedby a further solvent wipeuntil clean, will give goodperformance (except foracetal, polyethylene andpolypropylene and someother low surface energymaterials). This alsoapplies to powder coatpaints and other stovedpaint systems.

The same surfacepreparation will also givegood adhesion to metalsurfaces. The objective isto remove loosely attachedsurface films such as oils,waxes, dusts, mill-scale,loose paints and all other

surface contaminants inaddition to enhancingmechanical adhesion. Grit-blasting using a clean, finegrit also offers excellentadhesion on many metallicsubstrates.

Where humid environmentsare likely to be encounteredby metallic substrates werecommend additionalpriming with 3M Scotch-Weld 3901. Alternatively,chemical conversion coatingtechniques combined withpriming can offer the bestdurability.

Clean-Up:Excess uncured adhesivecan be removed with thefollowing solvents:

3M VHB Surface Cleaner(mild alcohol based cleaner)3M Scotch-Grip SolventNo2. (Ketone blend)3M Industrial Cleaner(Aerosol).

Additional ProductInformation

Please contact your 3MSalesperson for additionalinformation on thepreparation of difficultsurfaces, or likely exposureto aggressive environments.

4


Health & SafetyInformation

Precautions:Causes severe eye irritation,may cause permanent eyedamage. Irritating to skin.May cause sensitisation byskin contact. Avoid contactwith the skin and eyes.Wear suitable gloves andeye/face protection.

Launder contaminatedclothing before re-use.Avoid prolonged breathingof vapours. Avoidinhalation of dust whengrinding or cutting curedmaterial.

First Aid:

Eye Contact: Immediatelyflush eyes with copiousamounts of water for atleast 15 minutes, holdingeyes open. Call a physician.

Skin Contact: Washimmediately with plenty ofsoap and water.

For further informationplease contact theToxicology Department atthe Bracknell Head Officeon (0344) 858000.

3M, EPX, Duo-Pak, Scotch-Grip, Scotchbrite and Scotch-Weld are trademarks of the 3M Company.

Values presented have been determined by standard test methods and are average values not to be used for specification purposes.Our recommendations on the use of our products are based on tests believed to be reliable but we would ask that you conduct your own tests todetermine their suitability for your applications.This is because 3M cannot accept any responsibility or liability direct or consequential for loss or damage caused as a result of ourrecommendations.

Specialty Tapes & Adhesives 3M United Kingdom PLC 1996

3M United Kingdom PLC3M House,28 Great Jackson Street,Manchester,M15 4PA

Customer Service :

Tel 0161 236 8500Fax 0161 237 1105

3M Ireland3M House, Adelphi Centre,Upper Georges Street,Dun Laoghaire,Co. Dublin,Ireland

Customer Service :

Tel (01) 280 3555Fax (01) 280 3509

August 2000 Publication No. A 230 e GB Page 4 of 4 August 2000 Publication No. A 230 e GB Page 1 of 4

Lap shear strength versus heat ageing

Cure:16 hours/40°C Test: at 23°C, 50% rh

Lap shear strength versus tropical weathering (40/92, DIN 50015; typical average values)

Cure:16 hours/40°C Lap shear strength was determined after immersion for 90 days at 23°C in media shown.

Fatigue test on simple lap joints (DIN 53285)

Cure: 20 minutes/100°C Mean static lap shear strength: 16.3N/mm2Fluctuating load as % of static shear strength

302015

No. of load cycles to joint failure

105 - 106

106 - 107

> 107

Storage Araldite 2011/A and Araldite 2011/B may be stored for up to 3 years at room temperature provided the

components are stored in sealed containers. The expiry date is indicated on the label.

Handlingprecautions

Caution

Vantico products are generally quite harmless to handle provided that certain precautions normally taken when handling chemicals

are observed. The uncured materials must not, for instance, be allowed to come into contact with foodstuffs or food utensils, and

measures should be taken to prevent the uncured materials from coming in contact with the skin, since people with particularly

sensitive skin may be affected. The wearing of impervious rubber or plastic gloves will normally be necessary; likewise the use of eye

protection. The skin should be thoroughly cleansed at the end of each working period by washing with soap and warm water. The

use of solvents is to be avoided. Disposable paper - not cloth towels - should be used to dry the skin. Adequate ventilation of the

working area is recommended. These precautions are described in greater detail in Vantico publication No. 24264/3/e Hygienic

precautions for handling plastics products of Vantico and in the Vantico Material Safety Data sheets for the individual products.

These publications are available on request and should be referred to for fuller information.

VanticoAdhesives and Tooling

All recommendations for the use of our products, whether given by us in writing, verbally, or to be implied from the results of testscarried out by us, are based on the current state of our knowledge. Notwithstanding any such recommendations the Buyer shallremain responsible for satisfying himself that the products as supplied by us are suitable for his intended process or purpose. Sincewe cannot control the application, use or processing of the products, we cannot accept responsibility therefor. The Buyer shallensure that the intended use of the products will not infringe any third party’s intellectual property rights. We warrant that ourproducts are free from defects in accordance with and subject to our general conditions of supply.

Duxford, CambridgeEngland CB2 4QA

Tel:+44(0)1223832121Fax:+44(0) 1223 493322www.vantico.com

Vantico, 2000 Araldite is a registered trademark of Vantico AG, Basel Switzerland.

Adhesives and Tooling

Structural Adhesives

Araldite®® 2011 (AW 106/HV 953U)Two component epoxy paste adhesive

Key properties • High shear and peel strength

• Tough and resiliant

• Good resistance to dynamic loading

• Bonds a wide variety of materials in common use

Description Araldite 2011 is a multipurpose, two component, room temperature curing, paste adhesive of high strength and

toughness.

It is suitable for bonding a wide variety of metals, ceramics, glass, rubber, rigid plastics and most other materials

in common use. It is a versatile adhesive for the craftsman as well as most industrial applications.

Product data

2011/A 2011/B 2011 (mixed)

Colour (visual) neutral pale yellow pale yellow

Specific gravity ca. 1.15 ca. 0.95 ca. 1.05

Viscosity (Pas) 30-50 20-35 30-45

Pot Life (100 gm at 25°C) - - 100 minutes

Shelf life (2-40°C) 3 years 3 years -

Processing Pretreatment

The strength and durability of a bonded joint are dependant on proper treatment of the surfaces to be bonded.

At the very least, joint surfaces should be cleaned with a good degreasing agent such as acetone,

trichloroethylene or proprietary degreasing agent in order to remove all traces of oil, grease and dirt.

Alcohol, gasoline (petrol) or paint thinners should never be used.

The strongest and most durable joints are obtained by either mechanically abrading or chemically etching

(“pickling”) the degreased surfaces. Abrading should be followed by a second degreasing treatment

Mix ratio Parts by weight Parts by volume

Araldite 2011/A 100 100

Araldite 2011/B 80 100

Resin and hardener should be blended until they form a homogeneous mix.

Resin and hardener are also available in cartridges incorporating mixers and can be applied as ready-to-use

adhesive with the aid of the tool recommended by Vantico.

Application of adhesive

The resin/hardener mix is applied with a spatula, to the pretreated and dry joint surfaces.

A layer of adhesive 0.05 to 0.10 mm thick will normally impart the greatest lap shear strength to the joint.

The joint components should be assembled and clamped as soon as the adhesive has been applied. An even

contact pressure throughout the joint area will ensure optimum cure.

0 5 10 15 20 25 30 35

As-made value

20°C / 5 years

80°C / 60 days

80°C / 5 years

120°C / 60 days

N/mm 2

0 5 10 15 20 25 30

As-made value

After 30 days

After 60 days

After 90 days

N/mm 2


Mechanical processing

Specialist firms have developed metering, mixing and spreading equipment that enables the bulk processing of

adhesive.

Vantico will be pleased to advise customers on the choice of equipment for their particular needs.

Equipment maintenance

All tools should be cleaned with hot water and soap before adhesives residues have had time to cure. The

removal of cured residues is a difficult and time-consuming operation.

If solvents such as acetone are used for cleaning, operatives should take the appropriate precautions and, in

addition, avoid skin and eye contact.

Times to minimum shear strength

Temperature °C 10 15 23 40 60 100

Cure time to reach hours 24 12 7 2 - -

LSS > 1N/mm2 minutes - - - - 30 6


LSS > 10N/mm2 minutes - - - - 45 7

LSS = Lap shear strength.

Typical curedproperties

Unless otherwise stated, the figures given below were all determined by testing standard specimens made by

lap-jointing 170 x 25 x 1.5 mm strips of aluminium alloy. The joint area was 12.5 x 25 mm in each case.

The figures were determined with typical production batches using standard testing methods. They are

provided solely as technical information and do not constitute a product specification.

Average lap shear strengths of typical metal-to-metal joints (ISO 4587)

Cured for 16 hours at 40°C and tested at 23°C

Pretreatment - Sand blasting

Average lap shear strengths of typical plastic-to-plastic joints (ISO 4587)


Pretreatment - Lightly abrade and alcohol degrease.

Lap shear strength versus temperature (ISO 4587) (typical average values)

Cure: (a) = 7 days /23°C; (b) = 24 hours/23°C + 30 minutes/80°C

Roller peel test (ISO 4578) Cured 16 hours/40°C 5 N/mm

Glass transition temperature Cure: 16 hours at 40°C ca. 45°C

Electrolytic corrosion (DIN 53489) (cure 16hrs at 40°C or 20 mins at 100°C)

Test: 4 days in a conditioning chamber in 40/92 climate as specified by DIN 50015

Rating according to specified standard A -A/B 1,2

Minimum dielectric strength at 50 Hz, 24°C (VSM 77170)

Mix ratio Instantaneous value 1-minute value

100:80 pbw 25-27 kV/mm 22-24 kV/mm

Water vapour permeability (NF 41001) (38°C, 90% rh) Cure: 5 days/23°C

Test on a 1mm thick film 16g/m2/24 hours

Water absorption (ISO 62-80)

24 hours at 23°C 0.8%

30 mins at 100°C 1.3%

Thermal conductivitiy (ISO 8894/90) Cure: 20 minutes/100°C

Test: At 23°C 0.22W/mK

Shear modulus (DIN 53445) Cure: 16 hours/40°C

-50°C - 1.5GPa

0°C - 1.2GPa

50°C - 0.2GPa

100°C - 7MPa

0

10

20

30

40

-60 -40 -20 0 20 40 60 80 100°C

N/mm 2

a

b

0 5 10 15 20 25 30

As-made value

IMS

Gasoline (petrol)

Ethyl acetate

Acetic acid, 10%

Xylene

Lubricating oil

Paraffin

Water at 23°C

Water at 60°C

Water at 90°C

30 days 60 days 90 days

N/mm 2

Cure: 16 hour/40°C

0 5 10 15 20 25 30

Aluminium

Steel 37/11

Stainless steel V4A

Galvanised steel

Copper

Brass

N/mm 2

00 55 1010

SMC

ABS

Polycarbonate

PVC

Polyamide(nylon6)

N/mm 2

Degraded


Mechanical processing

Specialist firms have developed metering, mixing and spreading equipment that enables the bulk processing of

adhesive.

Vantico will be pleased to advise customers on the choice of equipment for their particular needs.

Equipment maintenance

All tools should be cleaned with hot water and soap before adhesives residues have had time to cure. The

removal of cured residues is a difficult and time-consuming operation.

If solvents such as acetone are used for cleaning, operatives should take the appropriate precautions and, in

addition, avoid skin and eye contact.

Times to minimum shear strength

Temperature °C 10 15 23 40 60 100


LSS > 1N/mm2 minutes - - - - 30 6


LSS > 10N/mm2 minutes - - - - 45 7

LSS = Lap shear strength.

Typical curedproperties

Unless otherwise stated, the figures given below were all determined by testing standard specimens made by

lap-jointing 170 x 25 x 1.5 mm strips of aluminium alloy. The joint area was 12.5 x 25 mm in each case.

The figures were determined with typical production batches using standard testing methods. They are

provided solely as technical information and do not constitute a product specification.

Average lap shear strengths of typical metal-to-metal joints (ISO 4587)


Pretreatment - Sand blasting

Average lap shear strengths of typical plastic-to-plastic joints (ISO 4587)


Pretreatment - Lightly abrade and alcohol degrease.

Lap shear strength versus temperature (ISO 4587) (typical average values)

Cure: (a) = 7 days /23°C; (b) = 24 hours/23°C + 30 minutes/80°C

Roller peel test (ISO 4578) Cured 16 hours/40°C 5 N/mm

Glass transition temperature Cure: 16 hours at 40°C ca. 45°C

Electrolytic corrosion (DIN 53489) (cure 16hrs at 40°C or 20 mins at 100°C)

Test: 4 days in a conditioning chamber in 40/92 climate as specified by DIN 50015

Rating according to specified standard A -A/B 1,2

Minimum dielectric strength at 50 Hz, 24°C (VSM 77170)

Mix ratio Instantaneous value 1-minute value

100:80 pbw 25-27 kV/mm 22-24 kV/mm

Water vapour permeability (NF 41001) (38°C, 90% rh) Cure: 5 days/23°C

Test on a 1mm thick film 16g/m2/24 hours

Water absorption (ISO 62-80)

24 hours at 23°C 0.8%

30 mins at 100°C 1.3%

Thermal conductivitiy (ISO 8894/90) Cure: 20 minutes/100°C

Test: At 23°C 0.22W/mK

Shear modulus (DIN 53445) Cure: 16 hours/40°C

-50°C - 1.5GPa

0°C - 1.2GPa

50°C - 0.2GPa

100°C - 7MPa

0

10

20

30

40

-60 -40 -20 0 20 40 60 80 100°C

N/mm 2

a

b

0 5 10 15 20 25 30

As-made value

IMS

Gasoline (petrol)

Ethyl acetate

Acetic acid, 10%

Xylene

Lubricating oil

Paraffin

Water at 23°C

Water at 60°C

Water at 90°C

30 days 60 days 90 days

N/mm 2

Cure: 16 hour/40°C

0 5 10 15 20 25 30

Aluminium

Steel 37/11

Stainless steel V4A

Galvanised steel

Copper

Brass

N/mm 2

00 55 1010

SMC

ABS

Polycarbonate

PVC

Polyamide(nylon6)

N/mm 2

Degraded


Lap shear strength versus heat ageing

Cure:16 hours/40°C Test: at 23°C, 50% rh

Lap shear strength versus tropical weathering (40/92, DIN 50015; typical average values)

Cure:16 hours/40°C Lap shear strength was determined after immersion for 90 days at 23°C in media shown.

Fatigue test on simple lap joints (DIN 53285)

Cure: 20 minutes/100°C Mean static lap shear strength: 16.3N/mm2Fluctuating load as % of static shear strength

302015

No. of load cycles to joint failure

105 - 106

106 - 107

> 107

Storage Araldite 2011/A and Araldite 2011/B may be stored for up to 3 years at room temperature provided the

components are stored in sealed containers. The expiry date is indicated on the label.

Handlingprecautions

Caution

Vantico products are generally quite harmless to handle provided that certain precautions normally taken when handling chemicals

are observed. The uncured materials must not, for instance, be allowed to come into contact with foodstuffs or food utensils, and

measures should be taken to prevent the uncured materials from coming in contact with the skin, since people with particularly

sensitive skin may be affected. The wearing of impervious rubber or plastic gloves will normally be necessary; likewise the use of eye

protection. The skin should be thoroughly cleansed at the end of each working period by washing with soap and warm water. The

use of solvents is to be avoided. Disposable paper - not cloth towels - should be used to dry the skin. Adequate ventilation of the

working area is recommended. These precautions are described in greater detail in Vantico publication No. 24264/3/e Hygienic

precautions for handling plastics products of Vantico and in the Vantico Material Safety Data sheets for the individual products.

These publications are available on request and should be referred to for fuller information.

VanticoAdhesives and Tooling

All recommendations for the use of our products, whether given by us in writing, verbally, or to be implied from the results of testscarried out by us, are based on the current state of our knowledge. Notwithstanding any such recommendations the Buyer shallremain responsible for satisfying himself that the products as supplied by us are suitable for his intended process or purpose. Sincewe cannot control the application, use or processing of the products, we cannot accept responsibility therefor. The Buyer shallensure that the intended use of the products will not infringe any third party’s intellectual property rights. We warrant that ourproducts are free from defects in accordance with and subject to our general conditions of supply.

Duxford, CambridgeEngland CB2 4QA

Tel:+44(0)1223832121Fax:+44(0) 1223 493322www.vantico.com

Vantico, 2000 Araldite is a registered trademark of Vantico AG, Basel Switzerland.

Adhesives and Tooling

Structural Adhesives

Araldite®® 2011 (AW 106/HV 953U)Two component epoxy paste adhesive

Key properties • High shear and peel strength

• Tough and resiliant

• Good resistance to dynamic loading

• Bonds a wide variety of materials in common use

Description Araldite 2011 is a multipurpose, two component, room temperature curing, paste adhesive of high strength and

toughness.

It is suitable for bonding a wide variety of metals, ceramics, glass, rubber, rigid plastics and most other materials

in common use. It is a versatile adhesive for the craftsman as well as most industrial applications.

Product data

2011/A 2011/B 2011 (mixed)

Colour (visual) neutral pale yellow pale yellow

Specific gravity ca. 1.15 ca. 0.95 ca. 1.05

Viscosity (Pas) 30-50 20-35 30-45

Pot Life (100 gm at 25°C) - - 100 minutes

Shelf life (2-40°C) 3 years 3 years -

Processing Pretreatment

The strength and durability of a bonded joint are dependant on proper treatment of the surfaces to be bonded.

At the very least, joint surfaces should be cleaned with a good degreasing agent such as acetone,

trichloroethylene or proprietary degreasing agent in order to remove all traces of oil, grease and dirt.

Alcohol, gasoline (petrol) or paint thinners should never be used.

The strongest and most durable joints are obtained by either mechanically abrading or chemically etching

(“pickling”) the degreased surfaces. Abrading should be followed by a second degreasing treatment

Mix ratio Parts by weight Parts by volume

Araldite 2011/A 100 100

Araldite 2011/B 80 100

Resin and hardener should be blended until they form a homogeneous mix.

Resin and hardener are also available in cartridges incorporating mixers and can be applied as ready-to-use

adhesive with the aid of the tool recommended by Vantico.

Application of adhesive

The resin/hardener mix is applied with a spatula, to the pretreated and dry joint surfaces.

A layer of adhesive 0.05 to 0.10 mm thick will normally impart the greatest lap shear strength to the joint.

The joint components should be assembled and clamped as soon as the adhesive has been applied. An even

contact pressure throughout the joint area will ensure optimum cure.

0 5 10 15 20 25 30 35

As-made value

20°C / 5 years

80°C / 60 days

80°C / 5 years

120°C / 60 days

N/mm 2

0 5 10 15 20 25 30

As-made value

After 30 days

After 60 days

After 90 days

N/mm 2

3Scotch-WeldTM

Epoxy Adhesive2216 B/A

Product Description 3M™ Scotch-Weld™ Epoxy Adhesive 2216 B/A is a flexible, two-part, roomtemperature curing epoxy with high peel and shear strength. Scotch-Weld epoxyadhesive 2216 B/A is identical to 3M™ Scotch-Weld™ Epoxy Adhesive EC-2216B/A in chemical composition. Scotch-Weld epoxy adhesive EC-2216 B/A has beenlabeled, packaged, tested, and certified for aircraft and aerospace applications.Scotch-Weld epoxy adhesive 2216 B/A may be used for aircraft and aerospaceapplications if proper Certificates of Test have been issued and material meets allaircraft manufacturer’s specification requirements.

Features • Excellent for bonding many metals, woods, plastics, rubbers, and masonry products.

• Base and Accelerator are contrasting colors.

• Good retention of strength after environmental aging.

• Resistant to extreme shock, vibration, and flexing.

• Excellent for cryogenic bonding applications.

• The tan NS Adhesive is non-sag for greater bondline control.

• The translucent can be injected.

• Meets DOD-A-82720.

Technical Data December, 2009

Typical UncuredPhysical Properties

Note: The following technical information and data should be considered representativeor typical only and should not be used for specification purposes.

Product 3M™ Scotch-Weld™ Epoxy Adhesive

2216 B/A Gray 2216 B/A Tan NS 2216 B/A Translucent

Base Accelerator Base Accelerator Base Accelerator

Color: White Gray White Tan Translucent Amber

Base: Modified Modified Modified Modified Modified ModifiedEpoxy Amine Epoxy Amine Epoxy Amine

Net Wt.: (lb/gal) 11.1-11.6 10.5-11.0 11.1-11.6 10.5-11.0 9.4-9.8 8.0-8.5

Viscosity: (cps) (Approx.)Brookfield RVF 75,000 - 40,000 - 75,000 - 550,000 - 11,000 - 5,000 -#7 sp. @ 20 rpm 150,000 80,000 150,000 900,000 15,000 9,000

Mix Ratio: (by weight) 5 parts 7 parts 5 parts 7 parts 1 part 1 part

Mix Ratio: (by volume) 2 parts 3 parts 2 parts 3 parts 1 part 1 part

Work Life: 100 g Mass @ 75°F (24°C) 90 minutes 90 minutes 120 minutes 120 minutes 120 minutes 120 minutes

3M™ Scotch-Weld™


Typical Cured Physical Properties


2216 Gray 2216 Tan NS 2216 Translucent

Color Gray Tan Translucent

Shore D Hardness 50-65 65-70 35-50ASTM D 2240

Time to Handling Strength 8-12 hrs. 8-12 hrs. 12-16 hrs.

Typical CuredElectrical Properties


2216 Gray 2216 Translucent

Arc Resistance 130 seconds

Dielectric Strength 408 volts/mil 630 volts/mil

Dielectric Constant@73°F (23°C) 5.51–Measured @ 1.00 KHz 6.3 @ 1 KHz

Dielectric Constant@140°F (60°C) 14.17–Measured @ 1.00 KHz —

Dissipation Factor 73°F (23°C) 0.112 Measured @ 1.00 KHz 0.119 @ 1 KHz

Dissipation Factor 140°F (60°C) 0.422–Measured @ 1.00 KHz —

Surface Resistivity@73°F (23°C) 5.5 x 1016 ohm–@ 500 volts DC —

Volume Resistivity@73°F (23°C) 1.9 x 1012 ohm-cm–@ 500 volts DC 3.0 x 1012 ohm-cm@ 500 volts DC

Typical Cured Thermal Properties


2216 Gray 2216 Translucent

Thermal Conductivity 0.228 Btu-ft/ ft2h°F 0.114 Btu-ft/ ft2h°F

Coefficient of Thermal 102 x 10-6 in/in/°C 81 x 10-6 in/in/°CExpansion between 0-40°C between -50-0°C

134 x 10-6 in/in/°C 207 x 10-6 in/in/°Cbetween 40-80°C between 60-150°C

Handling/CuringInformation

Directions for Use

1. For high strength structural bonds, paint, oxide films, oils, dust, mold release agentsand all other surface contaminants must be completely removed. However, theamount of surface preparation directly depends on the required bond strength andthe environmental aging resistance desired by user. For suggested surfacepreparations of common substrates, see the following section on surface preparation.

2. These products consist of two parts. Mix thoroughly by weight or volume in theproportions specified on the product label and in the uncured properties section.Mix approximately 15 seconds after a uniform color is obtained.

- 2 -

Typical Cured Outgassing Properties

% TML % CVCM % Wtr

3M™ Scotch-Weld™ Epoxy Adhesive 2216 Gray .77 .04 .23

Outgassing DataNASA 1124 Revision 4

Cured in air for 7 days @ 77°F (25°C).



Handling/CuringInformation (continued)

3. For maximum bond strength, apply product evenly to both surfaces to be joined.

4. Application to the substrates should be made within 90 minutes. Larger quantitiesand/or higher temperatures will reduce this working time.

5. Join the adhesive coated surfaces and allow to cure at 60°F (16°C) or above untilfirm. Heat, up to 200°F (93°C), will speed curing.

6. The following times and temperatures will result in a full cure:

7. Keep parts from moving until handling strength is reached. Contact pressure isnecessary. Maximum shear strength is obtained with a 3-5 mil bond line.Maximum peel strength is obtained with a 17-25 mil bond line.

8. Excess uncured adhesive can be cleaned up with ketone type solvents.*

Adhesive Coverage: A 0.005 in. thick bondline will typically yield a coverage of 320 sq. ft/gallon


2216 Gray 2216 Tan NS 2216 Translucent

Cure Temperature Time Time Time

75°F (24°C) 7 days 7 days 30 days

150°F (66°C) 120 minutes 120 minutes 240 minutes

200°F (93°C) 30 minutes 30 minutes 60 minutes

Application andEquipment Suggestions

These products may be applied by spatula, trowel or flow equipment.

Two-part mixing/proportioning/dispensing equipment is available for intermittent orproduction line use. These systems are ideal because of their variable shot size andflow rate characteristics and are adaptable to many applications.

Surface Preparation For high strength structural bonds, paint, oxide films, oils, dust, mold release agentsand all other surface contaminants must be completely removed. However, theamount of surface preparation directly depends on the required bond strength and theenvironmental aging resistance desired by user.

The following cleaning methods are suggested for common surfaces.

Steel or Aluminum (Mechanical Abrasion)

1. Wipe free of dust with oil-free solvent such as acetone or alcohol solvents.*

2. Sandblast or abrade using clean fine grit abrasives (180 grit or finer).

3. Wipe again with solvents to remove loose particles.

4. If a primer is used, it should be applied within 4 hours after surface preparation.

*When using solvents, extinguish all ignition sources, including pilot lights, andfollow the manufacturer’s precautions and directions for use. Use solvents inaccordance with local regulations.

- 3 -



Surface Preparation(continued)

Aluminum (Chemical Etch)

Aluminum alloys may be chemically cleaned and etched as per ASTM D 2651. Thisprocedure states to:

1. Alkaline Degrease – Oakite 164 solution (9-11 oz/gal of water) at 190°F ± 10°F(88°C ± 5°C) for 10-20 minutes. Rinse immediately in large quantities of coldrunning water.

2. Optimized FPL Etch Solution (1 liter):

Material AmountDistilled Water 700 ml plus balance of liter (see below)Sodium Dichromate 28 to 67.3 gramsSulfuric Acid 287.9 to 310.0 gramsAluminum Chips 1.5 grams/liter of mixed solution

To prepare 1 liter of this solution, dissolve sodium dichromate in 700 ml ofdistilled water. Add sulfuric acid and mix well. Add additional distilled water tofill to 1 liter. Heat mixed solution to 66 to 71°C (150 to 160°F). Dissolve 1.5grams of 2024 bare aluminum chips per liter of mixed solution. Gentle agitationwill help aluminum dissolve in about 24 hours.

To etch aluminum panels, place them in FPL etch solution heated to 66 to 71°C(150 to 160°F). Panels should soak for 12 to 15 minutes.

3. Rinse: Rinse panels in clear running tap water.

4. Dry: Air dry 15 minutes; force dry 10 minutes (minimum) at 140°F (60°C)maximum.

5. If primer is to be used, it should be applied within 4 hours after surfacepreparation.

Plastics/Rubber

1. Wipe with isopropyl alcohol.*

2. Abrade using fine grit abrasives (180 grit or finer).

3. Wipe with isopropyl alcohol.*

Glass

1. Solvent wipe surface using acetone or MEK.*

2. Apply a thin coating (0.0001 in. or less) of 3M™ Scotch-Weld™ StructuralAdhesive Primer EC-3901 to the glass surfaces to be bonded and allow the primerto dry a minimum of 30 minutes @ 75°F (24°C) before bonding.

*When using solvents, extinguish all ignition sources, including pilot lights, andfollow the manufacturer’s precautions and directions for use. Use solvents inaccordance with local regulations.

- 4 -



Typical AdhesivePerformanceCharacteristics

A. Typical Shear Properties on Etched AluminumASTM D 1002Cure: 2 hours @ 150 ± 5°F (66°C ± 2°C), 2 psi pressure

Overlap Shear (psi)

3M™ Scotch-Weld™ Epoxy Adhesive

2216 B/A Gray 2216 B/A Tan NS 2216 B/A Trans.Test Temperature Adhesive Adhesive Adhesive

-423°F (-253°C) 2440 — —

-320°F (-196°C) 2740 — —

-100°F (-73°C) 3000 — —

-67°F (-53°C) 3000 2000 3000

75°F (24°C) 3200 2500 1700

180°F (82°C) 400 400 140

T-Peel Strength (piw) @ 75°F (24°C)


2216 B/A Gray 2216 B/A Tan NS 2216 B/A Trans.Test Temperature Adhesive Adhesive Adhesive

75°F (24°C) 25 25 25

B. Typical T-Peel StrengthASTM D 1876

Shear ModulusTest Temperature (Torsion Pendulum Method)

-148°F (-100°C) 398,000 psi (2745 MPa)

-76°F (-60°C) 318,855 psi (2199 MPa)

-40°F (-40°C) 282,315 psi (1947 MPa)

32°F (0°C) 218,805 psi (1500 MPa)

75°F (24°C) 49,580 psi (342 MPa)

- 5 -



Overlap Shear (psi) 75°F (24°C)


2216 2216 2216B/A Gray B/A Tan NS B/A Trans.

Environment Time Adhesive Adhesive Adhesive

100% Relative Humidity 14 days 2950 psi 3400 psi@120°F (49°C) 30 days 1985 psi 2650 psi 1390 psi

90 days 1505 psi

*Salt Spray@75°F (24°C) 14 days 2300 psi 3900 psi30 days 500 psi 3300 psi 1260 psi60 days 300 psi

Tap Water@75°F (24°C) 14 days 3120 psi 3250 psi30 days 2942 psi 2700 psi 1950 psi90 days 2075 psi

Air@160°F (71°C) 35 days 4650 psi 4425 psi

Air@300°F (149°C) 40 days 4930 psi 4450 psi 3500 psi

Anti-icing Fluid@75°F (24°C) 7 days 3300 psi 3050 psi 2500 psi

Hydraulic Oil@75°F (24°C) 30 days 2500 psi 3500 psi 2500 psi

JP-4 Fuel 30 days 2500 psi 2750 psi 2500 psi

Hydrocarbon Fluid 7 days 3300 psi 3100 psi 3000 psi

Typical AdhesivePerformanceCharacteristics(continued)

C. Overlap Shear Strength After Environmental Aging-Etched Aluminum

Overlap Shear (psi) Time aged @ 300°F (149°C)

Test Temperature 0 days 12 days 40 days 51 days

-67°F (-53°C) 2200 3310 3120 2860

75°F (24°C) 3100 5150 4930 4740

180°F (82°C) 500 1000 760 1120

350°F (177°C) 420 440 560 —

D. Heat Aging of 3M™ Scotch-Weld™ Epoxy Adhesive 2216 B/A Gray(Cured for 7 days @ 75°F [24°C])

- 6 -

*Substrate corrosion resulted in adhesive failure.



E. Overlap Shear Strength on Abraded Metals, Plastics, and Rubbers.

Overlap shear strengths were measured on 1" x 1/2" overlap specimens. Thesebonds were made individually using 1" by 4" pieces of substrate (Tested perASTM D 1002).

The thickness of the substrates were: cold rolled, galvanized and stainless steel –0.056-0.062", copper – 0.032", brass – 0.036", rubbers – 0.125", plastics – 0.125".All surfaces were prepared by solvent wiping/abrading/ solvent wiping.

The jaw separation rate used for testing was 0.1 in/min for metals, 2 in/min forplastics, and 20 in/min for rubbers.

Overlap Shear (psi) @ 75°F (24°C)


Substrate 2216 B/A Gray Adhesive 2216 B/A Tan NS Adhesive

Aluminum/Aluminum 1850 2350Cold Rolled Steel/Cold Rolled Steel 1700 3100Stainless Steel/Stainless Steel 1900Galvanized Steel/Galvanized Steel 1800Copper/Copper 1050Brass/Brass 850Styrene Butadiene Rubber/Steel 200*Neoprene Rubber/Steel 220*ABS/ABS Plastic 990* 1140*PVC/PVC, Rigid 940*Polycarbonate/Polycarbonate 1170* 1730*Acrylic/Acrylic 1100* 1110*Fiber Reinforced Polyester/

Reinforced Polyester 1660* 1650*Polyphenylene Oxide/PPO 610 610PC/ABS Alloy / PC/ABS Alloy 1290 1290

*The substrate failed during the test.

- 7 -

Typical AdhesivePerformanceCharacteristics(continued)

Storage Store products at 60-80°F (16-27°C) for maximum storage life.

Shelf Life When stored at the recommended temperatures in the original, unopened containers,the shelf life is two years from date of shipment from 3M.



- 8 -

Refer to Product Label and Material Safety Data Sheet for health and safety information before using thisproduct. For additional health and safety information, call 1-800-364-3577 or (651) 737-6501.

PrecautionaryInformation

The technical information, recommendations and other statements contained in this document arebased upon tests or experience that 3M believes are reliable, but the accuracy or completeness of suchinformation is not guaranteed.

Technical Information

Unless an additional warranty is specifically stated on the applicable 3M product packaging or productliterature, 3M warrants that each 3M product meets the applicable 3M product specification at the time3M ships the product. 3M MAKES NO OTHER WARRANTIES OR CONDITIONS, EXPRESS ORIMPLIED, INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OR CONDITION OFMERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR ANY IMPLIED WARRANTYOR CONDITION ARISING OUT OF A COURSE OF DEALING, CUSTOM OR USAGE OF TRADE. If the 3M product does not conform to this warranty, then the sole and exclusive remedy is, at 3M’soption, replacement of the 3M product or refund of the purchase price.

Warranty, Limited Remedy, and Disclaimer

Except where prohibited by law, 3M will not be liable for any loss or damage arising from the 3M product,whether direct, indirect, special, incidental or consequential, regardless of the legal theory asserted,including warranty, contract, negligence or strict liability.

Limitation of Liability

This Industrial Adhesives and Tapes Division product was manufactured under a 3M quality system registered to ISO 9001:2000 standards.

ISO 9001:2000

Many factors beyond 3M’s control and uniquely within user’s knowledge and control can affect the useand performance of a 3M product in a particular application. Given the variety of factors that can affectthe use and performance of a 3M product, user is solely responsible for evaluating the 3M product anddetermining whether it is fit for a particular purpose and suitable for user’s method of application.

Product Use

Recycled Paper40% pre-consumer10% post-consumer

3Industrial Adhesives and Tapes Division3M Center, Building 225-3S-06St. Paul, MN 55144-1000800-362-3550 • 877-369-2923 (Fax)www.3M.com/industrial

3M and Scotch-Weld are trademarksof 3M Company.Printed in U.S.A.©3M 2009 78-6900-9583-7 (12/09)

BN 20146

Viti a testa cilindrica largaestremamente ribassata con cava esalobata, interamente filettate

INOX A2

A causa della geometria della testa e della tipologia di manovra,queste viti non sono idonee a trasmettere i carichi elevaticorrispondenti al precarico di riferimento!

Article# d1 d2 k max. a max. t max. A~ L

3233653 M2 4 1,27 1,2 X5 0,9 1,5 4

3233654 5

3233655 6

3233656 8

3233657 M2,5 5 1,37 1,35 X6 1 1,75 4

3233658 5

3233659 6

3233660 8

3233661 M3 6 1,37 1,5 X8 1,1 2,4 5

3233662 6

3233663 8

3233664 10

3233665 M4 8 1,5 1,6 X10 1,5 2,8 6

3233666 8

3233668 10

3233669 12

3233670 M5 9 1,5 2 X15 1,8 3,35 6

3233671 8

3233673 10

3233674 12

3233675 16

3233677 M6 10 1,5 2,5 X20 2,1 3,95 8

3233678 10

3233679 12

3233682 16

3233683 20

http://shop.bossard.com 04. May 2018 / Page 1 of 2 http://www.bossard.com

86 APPENDIX B. DATASHEET

List of Figures

1.1 Summary table of the elementary constituents of matter, quarks,leptons and gauge bosons (image courtesy of Fehling, Dave.The Standard Model of Particle Physics: A Lunchbox’s Guide.The Johns Hopkins University). . . . . . . . . . . . . . . . . . 2

1.2 Feynman diagrams for Charged Lepton Flavour Violating (CLFV)processes µ+N → e+N and µ→ eγ (source: Mu2e experi-ment data center). . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3 The Fermi National Accelerator Laboratory. . . . . . . . . . . 51.4 The Mu2e experimental apparatus. . . . . . . . . . . . . . . . 51.5 The Mu2e stopping target. It is made of 17 aluminum disks,

0.2 mm thick, spaced 5.0 cm apart along the Detector Solenoidaxis. The disks radii decrease from 8.3 cm at the upstream endto 6.53 cm at the downstream end. . . . . . . . . . . . . . . . 7

1.6 Mu2e tracker layout. Only electrons with energy above 53 MeVare recon-structed. Electrons with lower energy spiral in thenon-instrumented central region (source: Mu2e experimentdata center). . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.7 Map view of the Mu2e experimental area. The muon beam-line, the Production Solenoid, the Transport Solenoid and De-tector Solenoid are clearly visible. . . . . . . . . . . . . . . . . 9

2.1 Exploded CAD view of one disk of the Mu2e electromagneticcalorimeter (source: Mu2e experiment data center). . . . . . . 12

2.2 SiPM prototype produced by HamamatsuTM . . . . . . . . . 122.3 CAD model of the Mu2e electromagnetic calorimeter. The

20 custom crates which host the boards for voltage distribu-tion, slow controls and data acquisition are shown in grey andgreen; the calorimeter can be moved along the beamline on ahorizontal rail (source: Mu2e experiment data center). . . . . 14

2.4 CAD model of one DAQ crate (source: Mu2e experiment datacenter). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2.5 CAD model of one disk of the calorimeter (source: Mu2e ex-periment data center). . . . . . . . . . . . . . . . . . . . . . . 15

87

88 LIST OF FIGURES

2.6 CAD model of one front end unit. The brown structure is themechanical support of the SiPMs and the front end boards. . 16

2.7 CAD modes of the DAQ cooling system (source: Mu2e exper-iment data center). . . . . . . . . . . . . . . . . . . . . . . . . 18

2.8 CAD model of the cooling lines (source: Mu2e experimentdata center). . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.9 CAD model of the front end cooling system on the backplate.The 38 pipes and the two manifolds are clearly visible (source:Mu2e experiment data center). . . . . . . . . . . . . . . . . . 20

2.10 CAD model showing the connection between pipes and mani-folds, realized by Swagelok®VCR®connectors (source: Mu2eexperiment data center). . . . . . . . . . . . . . . . . . . . . . 21

2.11 Hydraulic scheme of the front end cooling system. For sim-plicity, only two front end units have been represented (source:Mu2e experiment data center). . . . . . . . . . . . . . . . . . 21

3.1 Schematic representation of a SiPM. a) SiPM back side withthe metal ring; b) SiPM front side with the six adjacent siliconlayers; c) main SiPM components: the sensitive silicon layer,the underfill resin layer, the G10 body and the metal contactwhich is asymmetric. . . . . . . . . . . . . . . . . . . . . . . . 24

3.2 Boundary condition chosen for the SiPM thermal simulation;(left) The temperature of the entire SiPM back side is fixedat the value of 0 ◦C; (right) the temperature of the siliconpieces on the front side is determined from the simulation fora dissipated power of 1 W. . . . . . . . . . . . . . . . . . . . . 26

3.3 SiPM temperature field determined by the thermal simula-tion. The asymmetric temperature distribution is due to theasymmetric G10 and metal distribution internal to the SiPM. 27

3.4 Front end electronic model. . . . . . . . . . . . . . . . . . . . 283.5 Schematic representation of the two alternative glue distribu-

tions on the copper support studied with the thermal simulation. 293.6 Schematic view of the internal part of the SiPM support; the

SiPMs is glued to the hidden lower surface. . . . . . . . . . . 293.7 Boundary conditions for the SiPM thermal simulation. . . . . 313.8 SiPM temperature with glue distribution type a. . . . . . . . 323.9 SiPM temperature with glue distribution type b. . . . . . . . 33

4.1 Schematic CAD representation of the backplate of one calorime-ter disk. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.2 Testing machine (Lloyd Instruments, series LR50KPlus). . . . 374.3 Testing machine accessories. . . . . . . . . . . . . . . . . . . . 374.4 Simple specimen used to define an equivalent length. . . . . . 384.5 Measurement of the PEEK specimen transverse dimensions. . 39

LIST OF FIGURES 89

4.6 Photograph of the five specimes after the tensile test. . . . . . 404.7 Stress strain diagram for PEEK . . . . . . . . . . . . . . . . . 414.8 Scheme of the step joint used for determinate the speed test. . 424.9 Roughness measurement with a profilometer. . . . . . . . . . 454.10 Adhesive application. . . . . . . . . . . . . . . . . . . . . . . . 464.11 Specimen cure. . . . . . . . . . . . . . . . . . . . . . . . . . . 464.12 Fishing line used to perform the test of the adhesive thickness. 484.13 Cure of the double scarf specimens. . . . . . . . . . . . . . . . 494.14 Adhesive stress components. . . . . . . . . . . . . . . . . . . . 504.15 Pictures of the samples and tools used to perform the tests. . 52

5.1 Schematic CAD representation of the backplate and coolinglines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

5.2 Examples of M2 tap-bolt inserted in a PEEK sample. . . . . . 545.3 M2 tap-bolt on PEEK . . . . . . . . . . . . . . . . . . . . . . 545.4 Cooling line with one spring pin hole at the center and one

loop on one side. . . . . . . . . . . . . . . . . . . . . . . . . . 565.5 Design of the cooling line with a central spring pin and a

lateral loop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

90 LIST OF FIGURES

List of Tables

2.1 Properties of 35% monopropylene glycol aqueous solution at−10 ◦C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.1 Thickness and thermal conductivity of the SiPM components. 253.2 Thickness and thermal conductivity of the SiPM components

implemented in the thermal model after the rescaling. . . . . 253.3 CsI properties needed for the radiation analysis. . . . . . . . . 30

4.1 Measure of the tensile specimen cross section. . . . . . . . . . 394.2 Maximum force, ultimate tensile strengths and Young’s mod-

ulus for the five specimens. . . . . . . . . . . . . . . . . . . . 424.3 Measured values of the roughness of the overlap length. . . . 454.4 Results of the adhesive step joint test. . . . . . . . . . . . . . 474.5 Measured values of the roughness of both sides of the double

scarf joint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494.6 Results of the adhesive double scarf joint test. . . . . . . . . . 50

91

92 LIST OF TABLES

Bibliography

[1] 3M. Glue datasheets. url: www.3m.com.

[2] Test & Calibration (STC) AMETEK Sensors. Lloyd LR50KPlus man-ual. url: www.ametektest.com.

[3] Araldite. Glue datasheets. url: www.aralditeadhesives.com.

[4] Marco Beghini. “Appunti di comportamento meccanico dei materiali”.2014.

[5] Marco Beghini. Lezioni ed esercitazioni di tecnica delle costruzionimeccaniche. 2013.

[6] Bossard. Screw catalog. url: www.bossard.com.

[7] ASTM International, ed. D 1002-01 Standard Test Method for Appar-ent Shear Strength of Single-Lap-Joint Adhesively Bonded Metal Spec-imens by Tension Loading (Metal-to-Metal). 2004.

[8] ASTM International, ed. D 2093-03 Standard Practice for Preparationof Surfaces of Plastics Prior to Adhesive Bonding. 2004.

[9] ASTM International, ed. D 3163-01 Standard Test Method for Deter-mining Strength of Adhesively Bonded Rigid Plastic Lap-Shear Jointsin Shear by Tension Loading. 2004.

[10] ASTM International, ed. D 4896-01 Standard Guide for Use of Adhesive-Bonded Single Lap-Joint Specimen Test Results. 2004.

[11] ASTM International, ed. D 638-03 Standard Test Method for TensileProperties of Plastics. 2004.

[12] ASTM International, ed. D 907-04 Standard Terminology of Adhesives.2004.

[13] Leonardo Lucchesi. “Design, thermal analysis and validation test of theMu2e electromagnetic calorimeter cooling system at Fermilab”. Masterthesis. Università di Pisa, 2017.

[14] Federico Mosti. “Design, thermal analysis and validation test of theMu2e electromagnetic calorimeter cooling system at Fermilab”. Masterthesis. Università di Pisa, 2017.

93

www.3m.com

www.ametektest.com

www.aralditeadhesives.com

www.bossard.com

94 BIBLIOGRAPHY

[15] Hamamatsu Photonics. SiPM datasheets. url: www.hamamatsu.com.

[16] Quadrant. Ketron 1000 datasheet. url: www.quadrantplastics.com.

www.hamamatsu.com

www.quadrantplastics.com

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