Simulation and preliminary test of different absorbers for the pCT calorimeter

Abstract

Abstract The proton calorimeter is a key component of proton computed tomography (pCT). It aims to measure the residual energy and momentum of protons after passing through a patient’s body. In this study, we designed the prototype of the pCT calorimeter by including six layers of the ALICE pixel detector (ALPIDE) and six layers of the absorber. The absorber materials are carbon fiber (C), copper (Cu), and aluminum (Al) with 1 mm and 2 mm thicknesses. The prototype was tested by the proton source at King Chulalongkorn Memorial Hospital (KCMH), Bangkok. The number of activated pixels and the cluster sizes in each ALPIDE sensor obtained from the pCT calorimeter is measured at different proton beam energies. Moreover, this conceptual design of the pCT calorimeter was simulated by the G4Beamline Monte Carlo programming. At a proton beam energy of 70 MeV in the pCT calorimeter, simulations indicated Cu as the most effective absorber. Experimental results largely corroborated this, with Cu followed by Al, and then C in effectiveness. Both Cu and Al were found suitable for the pCT calorimeter prototype.