Palestrante
Descrição
Starting 2025, the LHC and its experiments will enter into a new era, the era of the High Luminosity LHC (HL-LHC), a program aiming for high precision measurements in the Standard Model, exploration of new regions of the phase space and searches for signals of new physics through very rare processes. Colliding proton beams at $\sqrt{s}=14$ TeV, the HL-LHC will reach an instantaneous luminosity of 7.5 $\times 10^{34}\mathrm{cm}^{-2}\mathrm{s}^{-1}$. With 200 simultaneous collisions per bunch crossing, the very busy environment dominated by QCD jet production will make the tracking-vertex association and particle identification a very demanding task and many of the current detectors, trigger and data acquisition systems will not be able to retain their performance in this situation. Moreover, this high luminosity will give rise to a significant increase in the radiation dose, with the high rapidity regions being the most affected. To cope with these challenges, the experiments will have to resort to new systems using the state-of-the-art particle detectors in order to withstand years of radiation dose delivered by the HL-LHC. The ATLAS experiment will deploy a new semiconductor based system, the High granularity Timing Detector (HGTD), a 2m disk to be installed between the ATLAS barrel and the endcap ($2.4 < |\eta|< 4.0$) that will provide timing information in order to aid track-vertex association and pileup mitigation. The CMS will also rely on timing measurements for its future internal detector (MTD), while ALICE foresees a completely new semiconductor based detector in 2030 (ALICE3), with two timing layers devoted to particle identification up to $|\eta|< 4.0$ and able to provide a timing resolution better than 20ps. All these experiments will use or are considering the forefront technology in silicon timing sensors, the Low Gain Avalanche Detector (LGAD). Having an intrinsic gain of only a few tens, these silicon-based sensors can provide picosecond timing resolution while withstanding radiation doses that can reach up to $2.5 \times 10^{15} \mathrm{ncm}^{-2}$ and 2 MGy[Si]. LGAD based detectors can be built with millimetric segmentation and very thin, resulting in a low material budget. As part of the ATLAS Phase-II program, the group already participates since 2018 in the R\&D of LGAD sensors for HGTD and will soon start the prototypes qualification. In the near future, the experience gained in ATLAS will be extended to explore new semiconductor radiation sensors for low energy applications (synchrotron light) and for the recently proposed ALICE3 TOF timing layers.
| Key Words | UFSD, LGAD, Semiconductor sensors, HL-LHC |
|---|
