Evaluation on the Performance of CZT Detectors in Alpha Particle Detection with Experiment and Simulation

Benefitting from wide bandgap, high resistivity, and large atomic number, cadmium zinc telluride (CdZnTe, CZT) detectors are capable of room-temperature operation and high-energy photon detection. Over the past three decades, CZT has been utilized for gamma-ray and neutron detection. Despite the potential to be applied in surface contamination monitors and radioactivity meters, CZT is rarely utilized in alpha particle detection. In this chapter, we evaluate by experimentation and simulation the performance of an alpha particle detecting system that we designed and built. The response of the detector to electric signals, electronic noise, energy resolution, and electron mobility-lifetime product is measured in the experiment. The properties, such as energy deposition and corresponding position, of the interaction between CZT detector and alpha particle, are simulated by a Monte Carlo simulation toolkit Geant4, while the charge carrier transportation in CZT detector is simulated and analyzed with COMSOL, a finite element methods (FEM) simulation software. An alpha-particle spectrum is constructed according to the simulation results, and an energy resolution of 1.26% @ 5157 keV and 1.14% @ 5486 keV is obtained therein, which approaches the experimental one, 1.26% @ 5157 keV and 1.29% @ 5486 keV.