The technology of the particle accelerator and particle detector have always been pushing the development of the high energy physics physics. Generating high luminosity collision environment to pursue the high statistics while guarantee the good quality of the data is a challenging issue of all time.
In this thesis, the principle of the energy measurement as well as the feature of the calorimeter (Chapter 1) is described. The current status of the CMS apparatus and a brief introduction to the LHC (Chapter 2) is visited. As one of the future detector in the CMS, the HGCAL, have undergone years of the study, is proceeding to the final stage of the design. (Chapter 3) To deal with the high radiation and the pileup environment, silicon is chosen to be the active material for the high radiation region of the end-cap.
Moreover, HGCAL is a sampling calorimeter aims to record the shower development while maintain an acceptable energy resolution at the same time. Beam test is the most essential component in HGCAL plan to validate the idea of the calorimeter. The H2 beam line (Chapter 4), the setup for the HGCAL prototype with the module design (Chapter 5), include the readout ASICs are introduced (Chapter 6). The data reconstruction (Chapter 7) based on different ASICs and the MC generation (Chapter 8) is done before the detector performance study (Chapter 9).
The 2016 June test beam at CERN SPS has provided astonishing result in [6]. Despite of the studies listed in the paper, two more studies are done and shown in this thesis.
In the first study, two methods of the energy reconstruction of the prototype has been studied. The proposed SF method indicates better performance in the low energy region and giving a lower constant term in the energy resolution. The second studied has proven that the shower shape variable has a promising power to separate the e-like pion events with the normal electron events. At the mean time it also proved that the delta-ray candidates can be selected from the shower shape variable, which reveals the HGCAL has a potential to detect these events.
A newly developed Skiroc2cms ASIC which features several design of the official HGCROC (ASIC which will be used in the HGCAL detector) has been used in 2017/2018 test beams. Followed by the new chip, the reconstruction step of the 2017/2018 has been re-designed. Several issues are pointed out and milestones are achieved from the several test beam studies.
The future (2019) plan for the HGCAL beam test after the SPS shutdown will be replacing the existing components gradually to the official design. The high/low voltage supply, the readout board, the transceiver and FPGA between the readout board and the hexaboard, and finally the readout ASIC on the hexaboard.
On the other hand, the NTU side has also been assigned as a module assembly center (MAC) of the HGCAL project, which will produce 5000 8-inch HGCAL modules in the future. The design of the environment for storage and assembly tasks are undergoing, while the instruments are bought to get ready for the mass production.
With the TDR being approved in April 2018, the HGCAL project has stepped into the final stage of the design and prototyping. The detector has posted various challenges in the electronics, hardware, software as well as the engineering. Lots of issues have been understood while revealing new challenges. Despite all these ordeals, the HGCAL is definitely a worth expecting calorimeter.
References
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