1. Microchannel cooling Alessandro Mapelli CERN PH-DT EPFL-LMIS4 Reporting on behalf of D. Bouit, J. Daguin, L. Kottelat, J. Noel, P. Petagna – CERN PH-DT K. Howell – GMU (PH-UFT) G. Nuessle – UCL (PH-UFT) A. Pezous - CSEM P. Renaud – EPFL-LMIS4 September, 2 nd 2011 GTK working group meeting NA62 collaboration week, Mainz, Germany

2. Outline FABRICATION 1 – New calculations for ΔP from EN/CV-DC with optimized design (more details in separate presentation) 2 – Silicon plate pressure resistance 3 – Microfabrication advances PERFORMANCE 4 – Experimental results on T uniformity 5 – Thermal resistance studies 6 – Calculations about out of plane bending OPERATION / INTEGRATION 7 – Cooling plant design from EN/CV-DC (see separate presentation) 8 – Radiation resistance of C 6 F 14 9 – Activation of C 6 F 14 due to radiation September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany2

3. New calculations for optimal design from EN/CV-DC bring the maximum pressure in the silicon cooling plate down to 4 to 6 bars for configurations of interest. More details in separate presentation today. Pressure drop minimization September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany3

4. Full silicon cooling plate holds ≥ 18 bars. Critical point at the level of the manifold’s maximum width (1.6 mm). Safety factor: 3 to 5 Pressure resistance of silicon plate September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany4 Silicon thickness: 100 µm channels manifolds

5. Microfabrication advances September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany5 NA62 full silicon baseline proposal. Optimizing thinning steps (see samples). 150 200 80 100 ÷ 240 480 ÷ 760 280 Thinning by grinding Thinning by selective etching Limit of acceptance Drawing not to scale All dimensions in µm

6. Temperature distribution September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany6 Inlet Outlet Heater 1 Heater 2 Heater 3 1 2 3 45 6 7 8 9 10 1112 1314 15 1 11 6 15 5 10

7. Thermal Resistance - I September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany7 Materials:Colors: SiliconGreen PyrexYellow Araldite GlueGray KaptonBlue Setup A Setup B Setup C baseline 7 µm Measured and calculated thermal resistance for various configurations. Allows for estimation of temperature difference between heat sink and heat source. SetupCalculationsExperiments AXX BXX CX- (GTK chips) 525 µm 30 µm 7 µm 380 µm 100 µm 30 µm 115 µm 35 µm 100 µm

8. Thermal Resistance - II Materials: Thermal Conductivity [W/mK] Pyrex1.129 (CMI) Araldite Glue 0.3 Kapton1.2 (Dupont) Silicon196.5 ΔT= Change in Temperature R = Thermal Resistance P = Power K = Thermal Conductivity L = Thickness A = Surface Area of Heater Experimental Thermal Resistance: Theoretical Thermal Resistance: Power Input R pyrex R Glue R kapton Setup A Thermal Resistance Circuit R tot = R pyrex + R glue + R kapton ΔTΔT September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany8

9. Thermal resistance - III R (calculated) = 2.4 W/K R (measured) = 2.1 W/K R (calculated) = 0.52 W/K R (calculated) = 0.39 W/K R (measured) = 0.68 W/K September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany9 Setup A Setup B Setup C

10. Transients September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany We now consider the static behavior of the micro- channel cooling option as fully compliant with the GTK cooling specifications A systematic study of the dynamical behavior in typical off-design conditions has been launched (cooling failure and recovery, electronic failure, time for interlocking, repeated cycles, etc…) 10

11. Plate deformation - I Model with 3 boxes representing sensor, chips and silicon cooling plate Dimensions: mc plate: 150µm thick, 80mm x 60mm chips: 100µm thick, 60mm x 40mm sensor: 200µm thick, 60mm x 30mm Boxes are bonded together Bump bonds sensor-chips: 0.039 W/mK 25 µm Thermal interface chips - cooling plate: 0.03 W/mK 30 µm Heat source 48 W on front side of the chips Heat sink -25 °C on the backside of the cooling plate September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany11 micro channel cooling plate chips sensor Cooling plate chips sensor 48 W -25°C Calculated temperature difference between chips and cooling plate: ~2°C

12. no supportfixed point support, frictionless line support no supportsupports total deformation8.5µm17µm equivalent stress0.39MPa Plate deformation - II Note: in-plane deformation negligible

13. Cooling plant design Preliminary cooling plant design entrusted to EN/CV-DC (see separate presentation) Standard CERN procedures available for design/construction/operation/maintenance September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany13

14. Radiation effects on C 6 F 14 Radiation effects on fluid performance: none if pure –Chemical and radiolytical characterization of some perfluorocarbon fluids used as coolants for LHC experiments, M. Battistin, S. Ilie, R. Setnescu, B. Teissandier, EDMS Doc. # 804849 –C6F14 radiation hardness and purification test plan, Michele Battistin, Sorin Ilie, Evangelia Dimovasili, EDMS Doc. # 707732 Activation of C 6 F 14 after irradiation: –DGS/RP started simulations (no impact on operation, only needed to define maintenance access rules) September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany14

15. Assembly and Integration Main accent from now on on assembly and integration issues –starting from the experience of the crew that designed the jigs for the assembly of Totem detectors (made available to work with us) –the first and most important issue will be the detailed design of the gluing tool to integrate the cold plate and the GTK module. 2 students will work on electro-mechanical integration –1 student joined the team in September (6 months) –1 student will join the team in October (5 months) September 6th 2011A. Mapelli - NA62 Collaboration Week - Mainz, Germany15