Abstract
The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to 1034 cm−2s−1. Liquid argon (LAr) sampling calorimeters are employed for electromagnetic and hadronic calorimetry. The luminosity for the proposed High Luminosity LHC phase (HL-LHC) will increase up to 5×1034 cm−2s−1 with the goal of accumulating an integrated luminosity of 3000 fb−1. This is well beyond the values for which the detectors were designed. The electromagnetic and hadronic calorimeters will be able to tolerate the increased particle flux, but the performance of the forward calorimeter (FCal) will be affected. Two possible solutions for keeping the current performance are being discussed. The readout electronics will also need to withstand larger radiation environment. In the hadronic endcap calorimeter (HEC) cold GaAs preamplifiers are located inside the endcap cryostats. The properties of these devices have been investigated in recent proton and neutron irradiation tests to determine whether they must be replaced. In addition, the entire front-end readout system is not expected to survive the integrated luminosity at the HL-LHC and will be replaced. The description of the new readout system is presented.
Highlights
Background in the2012 run agreed with the simulation using FLUKA and GEANT4Expected neutron dose for ● Cold electronics- up to 1014 neq/cm2 (SF=2) ● hadronic endcap calorimeter (HEC) LVPS for High Luminosity LHC (HL-LHC)– 1.8x1012 neq/cm2 (SF=2)Qualification range of actual electronics → 2 x 4 HEC LVPS should be replacedRadiation qualification of power MOSFETs and logic devices has been started Current HEC LVPS 13_26Power MOSFETs for HEC LVPS HEC LVPS should be replaced in LS3 – components are evaluated: power MOSFETs (16 x 2)
Abstract The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-ofmass energies up to 14 TeV and instantaneous luminosities up to 1034cm-2s-1
Liquid argon (LAr) sampling calorimeters are employed for all electromagnetic calorimetry in the pseudorapidity region |η|
Summary
Limits on-detector data buffers prevent more advanced trigger algorithms On-detector digitization of all signals at 40 MHz → input to Level-0/Level-1 triggers. Instantaneous luminosities of 5 x 1034 cm-2s-1 → mean pile-up of 130 events Total luminosity of 3000 fb-1 → high total radiation doses A total of ~30 years of operation instead of anticipated 10 years. General trend: Data → for trigger and read-out ( 40 MHz) → improved and more complex trigger algorithms → off-detector buffers and pipelines. Install more radiation tolerant front-end components Accessible → replace complete readout chain. Hadronic LAr Endcap Calorimeter: pre-amplifier and summing boards inside endcap cryostat (optional replacement)
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