Philippe Grenier (CERN) ATLAS week, CERN October 2001 Cooling performances and tests during the September 2001 calibration period Fernando Varela / Philippe Grenier (CERN) ATLAS week, CERN October 2001

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Cooling system in H8 water tank output pipes fridge unit control box return pipes

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Monitoring of the cooling system cooling unit informations (ELMBs) - input/output temp on each drawer - water output temp - water flow drawer informations (HV program) - also, HV on the PMTs - 7 temp probes located in the drawers Monitoring PVSSII application Database (web interface)

Philippe Grenier (CERN) ATLAS week, CERN October 2001

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Low voltages control Drawer temperatures trends PMTs HVs

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Stability of the system normal working conditions: T=18 o C, Flow=60 l/h

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Stability of the system during data taking Tout =19.7  0.1 o C =19.6  0.1 o C =18.3  0.1 o C =18.4  0.1 o C =18.3  0.1 o C Tin

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Increase of the water temperature in the drawers ( o C)

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Stability of the temperature inside drawer

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Cooling tests 1- variation of the water input temperature (16 o C  22 o C) (180 GeV electrons shooting in cell A14)  PMT gain variation measured with particules  drawer temperatures variations 2- variation of the water flow (10 l/h  60 l/h)  drawer temperatures variations

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Water flow variations Cooling Temperature = 18 o C  optimal flow: 60 l/h

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Drawer temperatures variations Flow = 60 l/h 6 o C 3 o C  T(PMT) = 1/2  T(cooling)

Philippe Grenier (CERN) ATLAS week, CERN October 2001 PMT gain variation versus temperature  E/E = 0.2 % / o C(PMT)   E/E = 0.1 % / o C(cooling) resolution total energy deposited versus temperature in PMT# GeV electrons

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Conclusions - optimal flow: 60 l/h (without LV in fingers) -  T(output - input) = 1.3 o C, for a flow of 60l/h -  Gain(PMT) = 0.2% / o C(PMT) = 0.1% / o C(cooling) - cooling water temperature stability: 18.3  0.1 o C

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Still to be done - Effect of room temperature variation with non-isolated pipes (using foreseen tubes) - ( not yet operating: cooling unit for Cs calibration in blg 185 ready) - Next year: re-optimize flow with finger LV power supplies - Pilot Project (see next slide)

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Cooling pilot project in blg budget approved last week (50% financed by EP div JCOV committee) - real size test (ATLAS): note - Schedule (Sept Sept 2002): - 15m high scaffolding available - components just ordered - start mounting/piping, until end of the year - tests to be done: Jan 02  Sept 02

Philippe Grenier (CERN) ATLAS week, CERN October 2001 Cooling pilot project in blg 185: Scaffolding installation