Geant4 simulations of the lead fluoride calorimeter

TL;DR

This paper uses Geant4 simulations to analyze the emission processes in a lead fluoride calorimeter designed for the Fermilab muon g-2 experiment, focusing on Cherenkov, transition radiation, and other effects.

Contribution

It provides a detailed simulation of radiation processes in a complex calorimeter system, including spectral and angular distributions of Cherenkov photons and transition radiation.

Findings

Spectral and angular distributions of Cherenkov photons were evaluated.

Transition radiation and pre-shower distributions were analyzed.

Simulation results inform detector response and calibration strategies.

Abstract

In this paper we simulate the emission by charged particles in complex structures with help of Geant4. We take into account Cherenkov radiation, transition radiation, bremsstrahlung, pair production and other accompanying processes. As an application we investigate the full size electromagnetic calorimeter for the muon g-2 experiment at Fermilab. A calorimeter module (24 are expected in the experiment) consists of a Delrin front panel for installation of the laser calibration system, 54 PbF2 Cherenkov crystals wrapped by the black Millipore paper, and silicon photo-multiplier sensors. We report here on a simulation of radiation from positrons passing through the calorimeter system. We carry out the simulation using Geant4 toolkit, which provides a complete set of tools for all areas of detector simulation: geometry, tracking, detector response, run, event and track management, and visualization. We consider Cherenkov photons expansion when a positron moves down through the calorimeter at the arbitrary angle of incidence. Both spectral and angular distributions of Cherenkov optical photons in different parts of the calorimeter system have been evaluated as well as the transition radiation and pre-shower distributions from the panel and from the Al vacuum chamber of the storage ring. (The paper is in progress).