Speaker
Description
During Long Shutdown 3, the Large Hadron Collider (LHC) at CERN will undergo an upgrade program, marking the beginning of the High-Luminosity era. The High-Luminosity Large Hadron Collider (HL-LHC) is expected to collide protons at a centre-of-mass energy of 14 TeV and to reach the unprecedented peak instantaneous luminosity of 7 x 10^34 cm^-2 s^-1 with the average number of pileup events between 140 and 200. This will allow the ATLAS and CMS experiments to collect integrated luminosities up to 3000 fb^-1 over 10 years of data taking. To cope with this extreme scenario, the CMS detector will be substantially upgraded before the start of the HL-LHC, as part of the CMS Phase-2 Upgrade. The entire CMS tracking system will be replaced, in particular the Inner Tracker (IT). The new detector will feature increased radiation hardness, higher granularity, larger acceptance and capability to handle higher data rate and longer trigger latency. The upgraded IT will consist of a barrel part (TBPX) plus eight small disks (TFPX) and four large disks (TEPX) per side. The TEPX disks will host pixel modules arranged in five concentric rings and will extend the coverage up to |eta|=4.0. In this contribution the new TEPX detector is presented, with particular focus on its mechanical structure and thermal performance. Along with the other Inner Tracker sub-sections, TEPX features an effective CO2 cooling system integrated within a very light support mechanics, where power and data lines are also embedded. The cooling design implements titanium pipes to keep a low material budget while ensuring that the modules temperature remains well below the critical value to avoid thermal runaway. A pre-production prototype of the TEPX disk that will be installed in the final detector has been tested under operational conditions to assess its thermal behavior and several measurements have been carried out in different regions of the disk. A comparison between experimental results and thermal simulations performed using finite element analysis is presented, including studies of how improving the thermal conductivity of certain interfaces would affect performance. Finally, the extrapolation to end-of-life thermal behavior is discussed, accounting for the expected increase in power density and sensor leakage current over time.
| Track | Upgrades |
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