LHCb FT SiPM Cooling workpackage


As defined at the Heidelberg Workshop (April 2013) ( summary): PG advises, simulates. Imperial: engineering design and construction.


  • Assess and measure heat load
  • Demonstrate long operation, cycling, condensation
  • Thermal cycling to demostrate mechanical robustness, absence of leaks etc



Status summary:

05 July 2013

  • Chilled air cooling lab has been set up. A CTU student is working full-time on the air cooling tests. 4 different options of a cooling pipe will be tested: 3 round tubes with and without inner structures, a rectangular multi-finned radiator (baseline). Currently, the compressed air conditioning is being upgraded.
  • Full-scale mockup of a single end-cap, with 6 cm outer plug and ~13 cm support plate fragment has been constructed. It will be used mostly for the air-cooling tests.
  • The simulation work was paused since mid June, upon completion of the heat load study for the generic end-cap design. The result: 7.5 W per module side. The work will be resumed, once the consensus on the end-cap configuration has been achieved. The intermediate report will be ready shortly.
  • Preparation for the liquid cooling (2-phase) tests is ongoing. The tests will be performed at the TOTEM C3F8 -based facility. Mono-phase liquid cooling test setup is being designed (2-stage, with a -10C pre-cooler and a Peltier-based main cooler, down to -50C).
  • Useful links with the industry have been established in May-June: Institute of Thermoelectricity (UA) - specialized Peltier coolers, Thermacore Europe (UK) - low-temperature heat-pipes, composite heat-spreaders.

07 August 2013

  • The work on the air cooling tests continued in July. 4 different options of a cooling pipe have been tested with a full-scale end-cap mockup #1. The compressed air conditioning was upgraded by adding an industrial air dryer. The report is being prepared by the CTU team (expected date: August 10).
  • 2nd generation mockup was designed for the upcoming 2-phase cooling tests, using the concept discussed within the end-cap working group. The parts have been made, but not assembled, yet.
  • The simulation work is largely completed. The latest end-cap design has an estimated heat load of 5.7W per module side. In addition, promising results were obtained for "the cooling-though-flexPCB" option (to be discussed with the SiPM community). The summary report is under preparation.
  • The liquid cooling (2-phase) test bench at the TOTEM C3F8 -based facility has been prepared. The initial measurements, using a special thermostatic enclosure with a controlled thermal load, began this week.
  • Mono-phase liquid cooling test setup will be based on the the FPW-91 Julabo chiller, already delivered, to be installed at Point 8.
  • Negotiations with Thermacore Europe Ltd: an offer to design and manufacture prototype low-temperature ammonia-filled heat-pipes was received. Due to a high price, this option had been put on hold. Solid metal heat spreader with external Peltier chiller is a viable option for a BGV-like module design (discussed with Massi and Fred, TBD with Guido)

04 September 2013

  • 2-phase cooling tests started at the TOTEM test bench at H8, initially with a specially designed isothermal box containing a real cooling pipe (evaporator), a simulation of the end-piece and SiPM array, as well as a heater simulating a heat load of about 10W.
  • Results on temperature uniformity obtained, with different pressure differentials.
  • 2nd generation mockup , implementing the end-cap concept adopted in July, has been constructed and installed at the H8.
  • The JULABO chiller for single-phase liquid tests installed at Point 8, in the 2885/2-201 lab
  • A smaller new JULABO chiller F81ME /HL, intended for D-module cooling, will be ordered shortly

10 October 2013

  • 2-phase cooling tests continued with the new mockup, completed by September 16.
  • Two different insulation wall versions were tested. The total thermal load of the mockup was estimated as ~20W (including the external capillary and loosely insulated connection pipes), by observing the "dry-out" effect at the lowest temperatures at dummy SiPMs (down to -45...-48C). Under these conditions, the C3F8 -based system had to be operated with a significant underpressure on the suction side (0.42 bara).
  • The reports about summer tests have been prepared by the CTU group
  • A new round of thermal analysis: evaluation of local parameters of a 2-phase cooling scheme (capillaries, mass flows, thermal cycle)
  • First series of single-phase liquid cooling tests with the (borrowed) Julabo chiller: completed by October 1.
  • Ordered:a JULABO chiller F81HL, intended for D-module cooling; the delivery is expected this week.
  • Preparation of the SiPM cooling workshop of October 17

Thermal simulation

A CFD simulation Project Proposal (link to EDMS document). This project, joint with EN/CV, was intended to evaluate the heat load of the FT module end caps and give some insight for various prospective cooling options. Author: Enrico da Riva (CERN, EN/CV/PR).

  • all intermediate reports are available at the Project's DFS site, under Presentations
  • 2013-08-01: Addendum to 22/07: cooling through flex PCB.
  • 24/07/2013: latest end cap simulation results ("July" geometry). 5.7 W/module
  • 2013-06-10: 3D with Alu + edge insulation; multiport cooling pipe. 7.1 W/module
  • 2013-05-30: Alu jacket; liquid and air cooling estimates. 7.1 W/module
  • 2013-05-27a: First 3D results, more on liquid coolants. 3D≈2D
  • 2013-05-14: End caprefinements, liquid_coolants. 6.3...8.5 W/module
  • 2013-04-22: 2nd_round results: try to minimize the heat load. ~6 W/module
  • 2013-03-13: 1st round results: heat load with a simplified geometry. ~10 W/module
Bottom line: in the ideal case (with no inlet/outlet tubes, perfect thermal contacts) the heat load per module should be less than 10W. The T drop between the cooling pipe and the Si die strongly depends on the stiffener material. For FR4: ~7 (~5.7 W/module); for carbon: ~3 (~6.3 W/module)

Cooling options

  • Liquid cooling (mono-phase or 2-phase) - CERN, EN-CV group
  • C6K coolant
  • Air cooling - CERN, CTU
  • Hybrid options
    • Air, with pre-cooling - CERN, CTU
    • Liquid/thermoelectric - CERN, ITE
    • Heat pipe/thermoelectric - CERN, Thermacore (, ITE)
    • integrated TE cooling if SiPMs (a micro-Peltier module in the SiPM package) - proposed by ITE, currently this option is not pursued.


(Overview of main activities, transient activities are not mentioned). Completed activities are marked in green, ongoing in brown, scheduled in black, critical path -- red).


  • 1st round of thermal CFD analysis: head load and temperature profiles, mostly 2D (PG, EdR)
  • A feasibility study of the single-phase liquid cooling option (infrastructure) (PG, Julabo)
  • Order materials for the cooling mock-up(1), design of the 1st mockup version (PG)
  • Set up cooperation with the CTU(2) group (air and evaporative cooling options) (PG, RL, VV)
  • Set up cooperation with ITE(3) on the Peltier cooling option (PG, ITE) by end-May
  • Prepare the air cooling lab facilities (PG, GD)
  • Contacts with Thermacore Europe: "heat pipe" cooling option - weeks 1,3
  • 2nd round of CFD simulations: 3D, air cooling, heat load evaluation (EdR, PG) weeks 1-3
  • Start of the air cooling tests preparation phase, calibrations etc (PG, VV, MD) June 17
  • Construction of the 1st mock-up (GD, PG) by end-June
  • Draft report on the thermal simulation project (EdR, PG) week 1-2, pending
  • 3rd round of CFD simulations: new end-cap design, 2-phase cooling (EdR, PG) weeks 2-4
  • Air cooling tests, main phase (ME, PG) week 1-4
  • Liquid cooling tests (PG) weeks 2-4, shifted to September
  • Design and construct the 2nd version of the cooling mockup (PG, TS, GD) weeks 3-4
  • Preparation phase for the evaporative cooling option tests at H8 (VV, MD, GD) weeks 1-4
  • Intermediate report on the air and liquid cooling options tests (PG) end of July
  • Petr is away (vacations) 2-10 August, TBC
  • Final air cooling measurements (ME) weeks 1-2
  • Liquid cooling measurements with Julabo chiller(PG) weeks 3-4, shifted to September
  • Start of 2-phase measurements at H8 (MD) weeks 1 (or 2)
  • Possible follow-up of the joint ITE project on Peltier cooling (PG, ITE) about end-August mid Septenber
  • Draft summary report on the SiPM cooling, choice of the cooling option for the Demo (PG) end August- week 1 of September
  • Final 2-phase cooling measurements (MD, PG) weeks 1-2
  • Final report by the CTU group (VV, MD, ME) weeks 2-3
  • Integration with the Demo module (PG, TS, all) weeks 3-4 - postpopned
  • Work on the TDR section about the SiPM cooling (PG) postponed
  • Liquid cooling measurements with Julabo chiller(PG) weeks 4
  • Possible follow-up of the heat-pipe joint project with Thermacore Europe - on hold
(1) A full-scale model of the FT module end cap, intended to test various SiPM cooling options
(2) Czech Technical University, Prague. Group leader: Vaclav (Vic) Vacek
(3) Institute of Thermoelectricity, Chernovtsy, Ukraine. Director: Akad. Prof. L.I.Anatychuk


TBC to be confirmed

CTU Czech Technical University (Prague)
EdR Enrico da Riva (EN-CV-PJ)
GD Gerard Decreuse
ITE Inst. Of Thermoelectricity (Chernovtsy)
MD Martin Doubek (CTU)
ME Miroslav Erben (CTU)
PG Petr Gorbounov
RL Rolf Lindner
VV Vic Vaceck (CTU)
TS Trevor Savidge (IC)

Attached Documents

  • F.Tuma_c6K_as.....pdf: F. Tuma (3M Company) "Fluoroketone C2F5C (O)CF(CF3)2 as a Heat Transfer Fluid for Passive and Pumped 2-Phase Applications",full PDF version, difficult to find

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf F.Tuma_c6K_as.....pdf r1 manage 263.9 K 2014-10-15 - 20:16 PetrGorbounov F. Tuma (3M Company) "Fluoroketone C2F5C(O)CF(CF3)2 as a Heat Transfer Fluid for Passive and Pumped 2-Phase Applications",full PDF version difficult to find
PDFpdf Mockup2.pdf r1 manage 295.6 K 2013-08-07 - 22:14 PetrGorbounov Mockup-2 drawings
PDFpdf NOvec_Memo_1.3.pdf r2 r1 manage 539.6 K 2014-12-03 - 19:09 PetrGorbounov  
PDFpdf NW-CTU-for-LHCb-Aircooling-report_2013.pdf r1 manage 5782.4 K 2013-11-26 - 23:29 PetrGorbounov CTU Long write-up: SiPM cooling (vortex tubes)
PDFpdf NW_Final_ReportLHCbEvap_02.pdf r1 manage 3044.7 K 2013-11-26 - 23:30 PetrGorbounov CTU Long write-up: SiPM cooling (C3F8 evaporative)
PDFpdf Proceedings_03.07_submitted.pdf r1 manage 853.0 K 2014-07-06 - 21:02 PetrGorbounov Presentation at TIPP'2014 (SIPM cooling...)
PDFpdf SiPM_cooling_specs_1.1.pdf r1 manage 1625.1 K 2013-10-13 - 20:14 PetrGorbounov Draft specs on SiPM cooling
PDFpdf SiPM_cooling_specs_1.2.pdf r1 manage 1751.5 K 2013-10-16 - 19:38 PetrGorbounov Draft specs for SiPM cooling
PDFpdf Summary_2013.pdf r1 manage 98.8 K 2014-01-30 - 14:27 PetrGorbounov A summary of SiPM cooling tests in 2013
PDFpdf Summary_3.07.2013.pdf r1 manage 1099.2 K 2013-09-03 - 22:00 PetrGorbounov Summary of "Thermacore" option activities
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Topic revision: r17 - 2018-11-27 - BlakeLeverington
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