A simulation tool for designing and characterizing CdZnTe γ-ray detectors

This paper describes a new software tool developed for designing and characterizing CdZnTe γ-ray detectors. The tool includes three major components. The Geant4 toolkit is used for simulating gamma ray interactions and charge generation in the detector. A standard software package (ANSYS) is used for electrostatic field calculation inside the detector. The output of both codes is used as input in a custom developed charge transport simulation code. Drift and diffusion processes are simulated by solving Fokker-Planck equations, a method formally equivalent to the drift-diffusion equations of the carriers in the detector. Together, the three software packages allow to investigate time and spectrometric detector features. Therefore we can optimize the detector design for each specific application. The code has been validated by comparing simulation results with spectrum and waveforms measured from real detectors.