1. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling Visit of the President of the Munich Technical University LHC DETECTOR UPGRADES: COOLING Paolo Petagna (CERN PH/DT) The Present ATLAS and CMS Trackers Upgrade Challenges in Mechanical Engineering Detector Cooling Peculiarities Main R&D Issues on Cooling

2. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling ATLAS INNER DETECTOR: TRT -> Gas detector SCT -> 4088 Si modules (~3.3 M channels) PIX -> 1748 Modules (~80 M channels) 2,4 m End Caps – TEC (at the two ends, one shown only) Inner Barrel & Disks - TIB & TID - Outer Barrel - TOB - Pixel detector COOLING: LIQUID C6F14 (~50 kW) TRT COOLING: LIQUID C6F14 (~60 kW) SCT/PIX COOLING: EVAPORATIVE C3F8 (~60 kW) The Present ATLAS and CMS Trackers 6 m 2,3 m 6 m 7 m TRT Barrel TRT End Caps SCT Barrel SCT End Caps Pixel CMS TRACKER: Si-Strip TK -> 15232 Si modules (~9.6 M channels) 210 m2 Silicon sensors Pix TK -> ~1800 Modules (~60 M channels) 1 m2 Silicon sensors

3. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling LHC @ 2013-14 -> ATLAS & CMS upgrade « phase I »: upgrade PIX systems Enhanced electronics Reduced power consumption Minimized radiation lenght (~ mass) Lower temperature Enhanced cooling perfromance LHC -> SLHC (2017-18?) -> Complete upgrade of the ATLAS & CMS Trackers (« phase II ») 10 – 20 x track density : increase granularity 10 x irradiation level :decrease temperature Reduce material budget : minimze power densities optimize / stanadradize (layout) Enhance cooling performance Upgrade Challenges in Mechanical Engineering

4. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling Detector Cooling Peculiarities I: Long Distance Experimental CavernService Cavern ATLAS INNER DETECTOR COOLING PLANT: (simplified scheme) CMS TRACKER COOLING PLANT: (simplified scheme) Note: whatever stays in the Experimental Cavern must be - radiation tolerant - magnetic field tolerant

5. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling Detector Cooling Peculiarities II: System Complexity CMS TK cooling lines at/from distribution rack Arrival/departure of ATLAS ID services inside the experiment

6. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling Detector Cooling Peculiarities III: Geometrical Complexity and Mass Minimization Layout optimization for physics rules, cooling adapts (up to wich level?) Space optimization and need for “transparency” Impose minimization of pipe diameters and wall thickness Different geometrical arrangements require very different local thermal management solutions

7. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling Thermal contacts and joining techniques High thermal conductivity materials Pipe materials, joining and connections Leak measurements In-situ leak repair Instrumentation & diagnostic tooling Thermal modelling … more !? R&D Issues on Cooling I

8. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling Extremely good thermal properties Non toxic / Non aggressive Cheap Long-term available Environmental friendly Poorly activated R&D Issues on Cooling II Choice of cooling strategy for upgrades LIQUID Perfluorocarbon (C n F 2n+2 ) EVAPORATIVE Perfluorocarbon (C n F 2n+2 ) Other refrigerant (or mixture) CO 2

9. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling Extremely poor forecast possibility exists today for HIGH PRESSURE two-phase flows: even the most recent and successful models, like the “3-zones model” proposed by Consolini and Thome, providing relatively good forecast for HTC and  p of low pressure refrigerants, performs rather poorly on CO 2 and other refrigerant at high pressure. Experimental data are missing, in particular in “mini-channels” and in long channels of large cross section. A R&D collaboration is presently being organized between CERN (CRYOLAB and PH Dept.) and external partners. At the moment these include EPFL and University of Esslingen R&D Issues on Cooling III Physics of High-Pressure Two-Phase Flows

10. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling R&D Issues on Cooling IV Planned to have a standardized complete design (including controls) of a reproducible CO 2 cooling unit (say around 2 kW refrigerating power) in 1-2 years from now to be used as standard test unit for all partners and as scalable prototype for upgrade installation. Choice of the best suited thermodynamic cycle Choice of the components “Rackability” Reliability Control strategy CERN (PH Dept, Cryolab, EN Dept) NIKHEF (Amsterdam) SLAC (Berkeley) FNAL (Chicago) …OTHERS?

11. Meeting with TUM 1/5/2016P. Petagna – LHC Detector Upgrades: Cooling Process modeling and dynamic simulation (Collaboration with Université Joseph Fourier Grenoble) R&D Issues on Cooling V  Provide a basic model to study the steady state design Component tests and Prototype – Process: operating points, behavior, geometry study – Simulation steps Optimization of the components by data taking on the prototype Improved off-line model design  Provide a reliable model to study the dynamic performances and risks Control system design – Process: PLC and SCADA deployment, control logic production – Simulation steps Virtual commissioning of the whole control system  Ensure the quality of the source code before its implementation on the real plant Commissioning and operation – Process: validate the plant before its long-term operation – Simulation steps: Model calibration and Operator training Development of operation facilities (decision, troubleshooting, diagnostics, control, …)  Improve the performances and the reliability of the control system,  Improve efficiency in front of unforeseen situation understanding