Measurement of the inelastic pp cross-sections using the LHCb experiment and development of a new vertex detector

Abstract

In this thesis, measurements of the inelastic cross-sections of proton-proton collisions at centre-of-mass energies of \sqrt{s} = 5 TeV and \sqrt{s} = 13 TeV with the LHCb detector are presented. The cross-section measurements are performed using pp collisions with at least one prompt long-lived charged particle in the pseudorapidity range 2 < \eta < 5 and momentum p > 2 GeV/c. The extrapolation to the full phase-space is also performed using the official LHCb simulation generated using the Pythia 8 event generator. During the second long shut down of the LHC (2018-2019), the LHCb experiment will be upgraded, and all its subdetectors will be modified. Specifically, the Vertex Detector (VELO) will move from silicon strips to silicon pixels. The new readout ASIC will be the VeloPix, a successor of the Medipix family of ASICs. The Single Event Upset robustness of the Medipix3 chip, an ancestor of the VeloPix, is studied in order to evaluated the radiation hardness of the VeloPix. Different beam tests at a cyclotron facility were designed and performed with the subsequent data analysis. Using the Timepix3, a successor of the Medipix3, a telescope was developed. This telescope was designed to test the sensors and readout electronics prototypes for the VELO upgrade. The design and the performance of this telescope under very high particle incident rates are also presented.