Graham Beck 23 Jan Thermal QA Options for the Bare Stave (or Petal) Core ! This is about the production phase. ! Test Systems should be ~ identical (and users happy) across production sites. Primary purpose: Verify that core functions thermally i.e. will remove detector heat. Secondary: Check mechanical integrity i.e. find faults in stave construction. QA tests will apply to: Every stave / a fraction / none? … depending on yield and experience … and should cause minimal damage/degradation (e.g. non-contact). Candidate Tests: Suggest additions / alternatives / details (e.g. T ranges) ! 1)Thermal Performance: Fluid through pipe (e.g. CO 2 at operating T) + Surface thermal load. Check surface T distribution. 2)Thermal Cycling: e.g. -40C to +40C, followed by thermal/mechanical tests (tbd). 3)Thermal Shock: Robustness against switching Power and Coolant.

Graham Beck 23 Jan Issues: Expect flow rate LOW for 2mm id pipe (BNL to check full length tube) >5C T rise around loop. [FD flow calcns ok to ~ 20%. htc ≈ 4000 W/m 2 K ] * Worse performance for equivalent chiller in Europe (50Hz vs 60Hz). Precision IR measurements of absolute T unlikely: camera systematic errors (~ 4C vignetting, narcissus – also at QMUL). Thermal load poorly defined (but very similar to hybrid). IF flow acceptable, GOOD for comparative tests + localised fault finding. (Note BNL core pressure test does not check foam-pipe joint). Thermal Performance Test. What we have so far: BNL Chiller circulating LIQUID (hfe7100 ) at -35C. 6bar? Thermal load from ambient (box flushed with N 2 ) Surface T from scanned IR camera: – NON-contact! - Clearly finds missing glue between facing and foam (built-in faults, ≥20mm).

Graham Beck 23 Jan WARM liquid: A potentially quick, first stage test of thermal performance. e.g.hfe7100, +40C (chiller). Q transfer to ambient ≡ ~30% hybrid. Simple set-up: no N 2 box, easy IR view. Useful so far (but water used: eventually must replace by hfe due to corrosion risk). US Stave250 looked uniform. UK Plank7 : faults detected

Graham Beck 23 Jan Thermal Cycling QMUL “Coffin”: 2m Custom environmental chamber. Cold N 2 gas (Dewar boil-off at 77K) Switched (noisy) + Heaters. Fanned circulation. Large volume (stack several staves). Uses convective exchange with surface => ±50C cycle in 1 hour. Note: 20x more resistive than fluid flowing in tube. Does not use cooling tube, so useful for e.g. bus tapes pre-assembly (but a cooling tube based chamber could be faster?). Alternatives: BNL-like Chiller + hfe7100 (cooling pipe). In principle much faster (if well insulated) T Range: -40C to +50C. (-80C possible, see later). Issue: Cost TRACI Evaporative CO 2 (if adequate control) : -40 to about +15C only. For higher T would need test box with heating elements. Thermal Shock not investigated, but believed possible with CO 2 or Chiller+liquid.

Graham Beck 23 Jan Monophase (hfe7100) CO 2 TRACICO 2 Blow-off Lytron Chiller (AMS) Temp.range [C]-35 to to to +15 Pressure[bar] 6 10 – – 50 Programmable ? Yes Some.. No (e.g.Thermal Cycling)Low max T ProsOff-the-shelf.CO 2 – as ATLAS CO 2 – as ATLAS CONSFlow (poss. addEarly PhaseBuild effort (highP/lowT aux. pump?)Build effortManual control (politics)Bottle switching Capital cost [ £ ]38,000 (-80/+50C, hfe7100)50,000 initially? 5,000 19,000 (-40C. no hfe7100 cert.) Capability can usually be extended by investing £££s + technical expertise (where available). TRACI capabilities to be discussed with Lukasz Zwalinski (ff. feedback from today). Combinations of Liquid (chiller), Gas (N 2 cycling) and bi-phase (CO 2 ) to be explored.

6 ADDITIONAL Slides – QMUL TIM Tower: Re mod needed for BN/Hysol token measurements... A couple of Dave’s slides re pressurised core + laser surface profile… --- UK Thermomechanical Stave (2010) + Blow-off CO 2 : not a production core test: destructive since glued dummy hybrid heaters + ntcs. used). Graham Beck 23 Jan 2015

7 BNL making BN-Hysol samples for thermal conductivity: - centrifuge to de-gas. RT cure. - ZYP, PT140, PT180, Goodfellows × 10, 20, 30% by weight. - to Carl for thermal diffusivity apparatus. - to QMUL for TIMTower. Need re-build to better match thermal resistance => Replace Copper (385 W/mK) by Lead (35.3 W/mK).

Graham Beck 23 Jan Laser Surface height measurement (working on speeding up + reducing noise spikes) Detects built in missing glue faults (plus maybe an accidental one!)

Graham Beck 23 Jan 20159