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Detectors developments for the UA9 experiment at the CERN SPS
The research work documented in this thesis is done in a frame of the UA9 Collaboration at CERN. The main goal of the collaboration is the investigation of the high-energy particle beam collimation and extraction. The thesis is mainly devoted to the developments of detectors and the consequent exper...
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Lenguaje: | eng |
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U. Paris-Saclay
2019
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Acceso en línea: | http://cds.cern.ch/record/2693714 |
Sumario: | The research work documented in this thesis is done in a frame of the UA9 Collaboration at CERN. The main goal of the collaboration is the investigation of the high-energy particle beam collimation and extraction. The thesis is mainly devoted to the developments of detectors and the consequent experimental setups implemented at the SPS or LHC circulating machines at CERN. Regarding the nature of the charged particle interaction with a monocrystalline structure, a curved crystal can be used for the steering of the high-energy particle beam by means of the particle channeling between atomic planes of the crystal. Such a phenomenon is intensively studied by the UA9 Collaboration. Therefore, one of the main goals of the presented research is to develop sensitive devices for measuring the flux and the beam characteristics of the particles deflected by the crystal at the circulating machines. The detectors studied for this thesis are Cherenkov (CpFM) and pixel (Timepix). Since 2015, the CpFM (Cherenkov detector for proton Flux Measurement) has undergone various modifications to improve the particle counting characteristics. The range of the device operation varies from 1 to 1000 particles per bunch (~3 ns) with the particle resolution of less than 20% per single proton. Working in the primary vacuum of the accelerator and at high radiation doses, the detector showed high stability with the possibility to perform beam contamination studies. In turn, the Timepix detector has been calibrated at the extraction beamline and SPS accelerator, working in the secondary vacuum of the Roman Pot. A significant part of the thesis is devoted to the characterization and calibration of these detectors with the software developments for data acquisition and analysis. In this thesis, we also make a proposal for the measurement of the magnetic dipole moment (MDM) of short-lived baryons. The MDM is an important characteristic of the particle interaction with an external magnetic field. For the thesis, we concentrate on the measurement of the LambdaC+ MDM, which could provide information on the gyromagnetic (g) factor of the charm quark. Any discrepancy from g=2 will indicate a possible composite structure of the c-quark and clearly physics beyond the Standard Model (SM). So far, no experimental measurements of this value of baryons with heavy flavoured quarks have been carried out due to a short decay length of these particles (about 60 um). The proposal made in this thesis is to produce charm baryons by a strong interaction of the extracted proton beam (using a first bent crystal) impinging onto a target followed by the second large angle bent crystal (of several mrad) to channel the baryons and to rotate their polarization vector. This configuration is called a double-crystal setup and the experiment is proposed to take place at the LHC. In this thesis, I concentrate mainly on all the tests and validation needed at the SPS prior to the implementation at the LHC. A possible experimental configuration for the MDM measurements at the SPS is also proposed with an estimation of the absolute error of the measured g-factor value for the LambdaC+ baryon. |
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