26 May 2010Hans Postema - CERN Status and plan for the development and construction of CO2 Cooling System for Pixel Upgrade 1

Why CO2? Radiation hard Not electrically conductive, non corrosive Not flammable, not toxic Has excellent thermodynamic properties for micro- channels. Low dT/dP Low mass Low liquid/vapour density ratio Low viscosity High latent heat High heat transfer coefficient Environmental friendly Hans Postema - CERN26 May 20102

Pressure advantage Intuitively, higher pressures seem a disadvantage but: Gas flow at higher pressures needs smaller pipe diameters Pressure drops due to flow become less significant, allowing smaller pipes Small pipes can easily support the required pressures Hans Postema - CERN26 May 20103

Selection Many activities in different places Good overview requires several hours Global overviews risk to be repeating themselves through the year This presentation is a selection of some important achievements over the last few months Hans Postema - CERN26 May 20104

FPIX tube (February) Hans Postema - CERN26 May 20105

FPIX in fridge Hans Postema - CERN26 May 20106

Layout of the test section Length of the tube: 1m Inner diameter:1.4mm Wall thickness:100µm 13 temperature sensors glued on the tube Copper blocks for power supply

Improved insulation Environment influences obviously the readings of the sensors Better insulation of the tube needed Freezer must be at the same temperature as the cooling fluid Kapton tapeTubeArmaflex

Improvements Better results through insulating the tube and keeping the temperature inside the freezer at the temperature of the liquid

Temperature drop vs. tube length at 0°C Sensor 1 and 13 are before or after the heated test section

Temperature drop vs. tube length at -15°C Sensor 1 and 13 are before or after the heated test section

Comparison to correlations Temp.ThomeFriedelTest 1Test 2 Temperature drop 9°C 0.34 °C0.27 °C0.05 °C0.18 °C Pressure drop0.35 bar0.32 bar0.34 bar0.36 bar Temperature drop 0°C 0.37 °C 0.49 °C0.52 °C Pressure drop0.43 bar0.38 bar0.50 bar0.59 bar Temperature drop -15°C 0.39 °C0.49 °C0.82 °C0.89 °C Pressure drop0.61 bar0.68 bar1.25 bar1.37 bar Temperature drop -30°C 0.47 °C0.67 °C1.41 °C1.46 °C Pressure drop1.05 bar1.33 bar3.63 bar3.93 bar

Tsat=9°

Tsat=0°

Tsat=-15°

Tsat=-30°

Conclusions of tests Software of some correlations now fully debugged an operational Interesting differences between calculations and measurements remain FPIX tube can reliably cool the requested heat load of 124 W dT over tube length < 3 degrees C dT due to HTC < 3 degrees C Hans Postema - CERN26 May

18 May 2010 Reached an important milestone First time that the Full Scale cooling plant test setup was running No problem in priming the pump Pump runs very quiet and smooth, no vibrations The result of a year of work by a dozen people Hans Postema - CERN26 May

Cooling plant Hans Postema - CERN26 May

Including dummy load Hans Postema - CERN26 May

Chiller part Hans Postema - CERN26 May

View with control rack Hans Postema - CERN26 May

Hans Postema - CERN26 May

Control interface Hans Postema - CERN26 May

Next steps Commissioning of the plant at ambient temperature Test run of Atlas IBL cooling loop Installation of accumulator, required for low temperature operation Commissioning of the plant at low temperature Hans Postema - CERN26 May

Strategy (1) CO2 cooling plants cannot be bought off the shelf Relevant experience is not available in industry Current activities are generating the necessary experience “in house” Future CO2 cooling plants shall be designed and constructed “in house” Hans Postema - CERN26 May

Strategy (2) Cooling plant shall be constructed early, leaving 1 year for commissioning on the surface and 1 year for installation in UX To avoid schedule constraints, one cooling plant foreseen for detector commissioning in TIF, and one for installation in the CMS cavern Hans Postema - CERN26 May

Qualification Engineering and design shall follow the principles applied in aero-space or safety critical industrial applications Excellent workmanship shall have a priority over low-cost Extended “burn in” period necessary, comparable with satellites (1 year) Hans Postema - CERN26 May

Safety High pressure is a safety concern when combined with larger volumes (stored energy) Pipe-work and components are in PED class 1 (Pressure Equipment Directive) DN<32 requiring “Good Practice” Storage tanks or Accumulators are in class 4 requiring certification Accumulator for the full scale test setup will be produced with a CE certificate, by NIKHEF Hans Postema - CERN26 May

Schedule 2010 – Testing of Full Scale setup – Engineering and design of detector parts, pipe-work, fittings and final plant 2013 – Construction of cooling plants 2014 – Burn in of cooling plants in TIF 2015 – Installation cooling plant in UX 2016 – Installation of detector Hans Postema - CERN26 May

Participating groups CERN – Atlas CERN – CMS CERN – PH-DT CERN – EN-CV CERN – Cryolab EPFL Lausanne Fermilab IPN Lyon NIKHEF Atlas LHCb PSI RWTH Aachen SLAC Atlas University Esslingen University Karlsruhe Hans Postema - CERN26 May