Microchannel Cooling P Petagna Acknowledging contributions from A

Micro-channel Cooling P. Petagna Acknowledging contributions from: A. Francescon; A. Mapelli; H. Michaud; M. Morel; J. Noel; G. Nuessle; G. Romagnoli May 23 rd, 2013 - CSEM-CERN Meeting P. Petagna: Micro-channel Cooling

Thermal Management of Tracking Detectors: Basics • Power densities involved ~ 0. 5 -5 W/cm 2 • Large surfaces of silicon in tightly confined volumes • Total thermal dissipation up to few tens of k. W • Detector layout packed and geometrically complex, thus only limited space is available for piping and connections. • In many cases, in order to preserve the silicon sensor from severe degradation caused by the high level of radiation, it is also necessary to operate and maintain the detectors at temperatures in the range -10 to -20 °C • Parameters to be minimized: o The amount of material crossed by particles; o The temperature difference between heat source and heat sink for a given quantity of heat to be removed; o The temperature gradients on the surface of the sensor May 23 rd, 2013 - CSEM-CERN Meeting P. Petagna: Micro-channel Cooling

Examples of Solutions Adopted in the Present LHC Detectors ATLAS PIXEL CMS TEC Complex networks of mm-size metallic pipes brought in connection with the heat sources through customized low mass heat spreaders. A. Andreazza – ATLAS Coll. “Status of the ATLAS Pixel Detector at the LHC and its performance after three years of operation” NIMa, 2013 http: //dx. doi. org/10. 1016/j. nima. 2013. 045 CMS PIXEL Small contact surfaces + long chains of thermal resistances temperature difference between the module surface and the coolant typically ranges between 15 and 25 °C for electronics power densities generally not exceeding 2 W/cm 2. CMS TIB W. Erdmann - the CMS pixel group “The CMS pixel detector”, World Scientific Review Volume, 2009 May 23 rd, 2013 - CSEM-CERN Meeting P. Petagna: Micro-channel Cooling

Main Issues with Present “Standard” Solutions Example of material budget distribution for CMS PIX q Impact of cooling material on detector’s material budget q Very low refrigerant temperature for cold sensor operation q Concentrated heat sink under the ASICS must indirectly keep the sensor cold q Small natural surface of thermal exchange q Large CTE mismatch between heat source and metal heat sink May 23 rd, 2013 - CSEM-CERN Meeting P. Petagna: Micro-channel Cooling

Detector Silicon Micro-channel Cooling: Concept ORIGINAL CONCEPT (for high power IC): Tuckerman, D. B. , and Pease, R. F. W. , “High Performance Heat Sink for VLSI, ” IEEE Electron Dev. Lett. , EDL-2, No. 5, 1981 May 23 rd, 2013 - CSEM-CERN Meeting P. Petagna: Micro-channel Cooling

Advantages of Silicon Micro-channel Cooling why? q Silicon heat sink => Low mass q Distributed cooling in the substrate => Direct cooling both of ASICS and Sensor q Many parallel channels => Large heat exchange surface q Refrigerant flow distributed in small channels => High Heat Transfer Coefficient q No heat flows in the electronics/sensor plane => Small thermal gradients across the module q All material is silicon => No mechanical stress due to CTE mismatch May 23 rd, 2013 - CSEM-CERN Meeting P. Petagna: Micro-channel Cooling

NA 62 GTK: First Application of Silicon Micro-channel Cooling Silicon m-fabricated cooling device Hydraulic optimization: EN/CV CFD team AM BE Sensor and read-out chips OPERATIONAL SPECS: Detector surface: ~40 x 60 mm Sensor surface: ~30 x 60 mm Power dissipation (chips): • ~4 W/cm 2 on periphery • ~0, 5 W/cm 2 under the sensor Very high radiation level Sensor T < 0 °C (as low as possible) T uniformity on sensor: ± 3 °C Max cooling X-section in active area: eq. to 150 mm Si May 23 rd, 2013 - CSEM-CERN Meeting Adopted solution P. Petagna: Micro-channel Cooling

NA 62 GTK: Thermal and Mass Performance 150 parallel channels 70 x 200 mm Deeper manifolds for DP reduction Thickness in active area: 130 mm Max thickness outside active: < 700 mm DT Line 3 Line 2 sensitive area Performance @ 48 W (~1. 5 x nominal): Min DT sensor – fluid = ~ 6 °C (center) T uniformity on sensor = ± 3 °C DP (8 g/s C 6 F 14 @ -20 °C) = 8 bars Tests under vacuum Line 1 DT = 25 °C DT = 0 °C May 23 rd, 2013 - CSEM-CERN Meeting P. Petagna: Micro-channel Cooling

Other Examples of Application under Study ALICE ITS “Phase I” upgrade Room Temperature Two-phase refrigerant Low pressure Horizon 2015 20 °C 0 power 1. 5 W nominal 36 W ATLAS Inner PIXEL “Phase II” upgrade Cold Temperature Two-phase refrigerant High pressure Horizon 2018 - 10 °C May 23 rd, 2013 - CSEM-CERN Meeting P. Petagna: Micro-channel Cooling

Directions for further Integration Miniaturized reliable fluidic connections May 23 rd, 2013 - CSEM-CERN Meeting Integrated front-back electrical connections P. Petagna: Micro-channel Cooling

CERN-CSEM Collaboration AGREEMENT KN 2037/KT/PH/173 C Technical objectives of common interest Matching of resources Fixed (but realistic!) schedule Protection of background IP IP sharing of produced know-how May 23 rd, 2013 - CSEM-CERN Meeting P. Petagna: Micro-channel Cooling