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INTAS Progress Report 2007 : INTAS-CERN 05-103-7555 Title : A proposal for R&D to establish the limitations on the operation of the ATLAS end-cap calorimeters at high LHC luminosity Coordinators : Peter Schacht, Sergei Denisov Start date : 8. 5. 2006. Reducing gap size, shaping time….
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INTAS Progress Report 2007: INTAS-CERN 05-103-7555 Title: A proposal for R&D to establish the limitations on the operation of the ATLAS end-cap calorimeters at high LHC luminosity Coordinators: Peter Schacht, Sergei Denisov Start date: 8. 5. 2006
Reducing gap size, shaping time… “dE/dx” + ohmic heating Additional cooling loops in critical places, more powerful HV power supplies In HEC and EMEC, should not exceed 5 %. In FCAL ~ 64 V at nominal of 250 V. The resistors sit on the rear HEC side. Energy fluxes at L=1034: η = 2.5 5.0*105 GeV/cm2/s η = 3.2 2.5*106 GeV/cm2/s η = 4.9 2.0*108 GeV/cm2/s Main factors: ion’s mobility and recombination. Signal starts to degrade significantly above critical charge density.
Radiational damage of materials, activation β-decay of Ar41: = 6560 s After 100 days running at L=10**34: 98 GBq in EMEC, 50 in Barrel, 11 in HEC, 1.1 in FCAl_1, 0.5 in FCAl_2,3 After 7 more days of cool-down: 9.7 GBq in EMEC, 2.1 in Barrel, 6.5 in HEC, 19 in FCAl_1, 600 (?) in FCAl_2,3
LHC schedule (L.Evans & Dec 2006 Council): last magnet installed March 07 machine closed August 07 450 GeV (lum~1029:1030, 75 ns between bunch crossings) November 07 7 TeV August 08 Calorimeters (plan of 20 February): end of access to ECA - end of June, Barrel A – 15 July, Barrel C and ECC – 15 August Problems: calorimeters - LV power supplies (BNL and CERN, modified version should be supplied starting from April) Inner detector - SCT and TRT - heaters problem, Pixels on retard LHC - failure of support structure of final focus “inner triplet” superconductive quadrupoles (1 of 28, all assembled by FNAL) during pressure test 27 March