Simulation studies of the dual radiator RICH of the ePIC experiment at EIC

The goals of this thesis are original simulation studies contributing to the design of
the dual radiator Ring Imaging CHerenkov counter (dRICH) of the ePIC experiment
at the Electron-Ion Collider (EIC). The context of these studies is provided in
Chapter 1, where an introduction to the physics scope of the EIC and the ePIC
experiment is provided, Chapter 2, which introduces the EIC project and the
ePIC experiment, in Chapter 3, where basic concepts about particle identification
by Cherenkov techniques are recalled and Chapter 4, which describes the overall
particle identification system of the ePIC experiment.
The original studies, performed by the student author of this thesis, are reported
in Chapter 5. Three issues relevant for the dRICH design have been addressed,
two of them related to the novelty of the selected sensors of single photons, namely
Silicon PhotoMultipliers (SiPM), this being the first time they are used in a
Cherenkov imaging detector:
• The dependence of the dRICH performance versus the parameters of one of the
two radiators, the aerogel, in view of optimizing the choice of the parameters
to be fixed for this radiator.
• The distributions of the angles of the Cherenkov photon trajectories respect
to the photosensor surface; this information is relevant as, when the trajectory
is far from the orthogonal direction, the optical properties of the entrance
window of the photosensor can reduce the number of detected photons.
• A feature of the selected photosensors is the relevant dark count rate, where
the dark signals are non distinguishable from the single photon signals. The
presence of this background affects the dRICH performance. The studies
presented in this thesis are the first estimation of the dRICH performance
degradation caused by the dark counts.
The impact of the studies performed within this thesis is underlined in Chapter 6.