Pulse shape analysis for electron mobility study in cadmium zinc telluride gamma-ray detectors

A pulse shape analysis technique was implemented to determine the electron mobility μ_e and the electron mobility lifetime product μ_eτ_e in cadmium zinc telluride detectors (CZT). The digital gamma finder (DGF-4C) a single-width CAMAC module produced by X-Ray Instrumentation Associates (XIA), was used to extract pulse height, pulse shape, and signal rise time information. Data analyses using the extracted information allowed measuring the μ_e and μ_eτ_e in selected CZT samples. An almost linear relationship was observed for the signal rise time as a function of the inverse bias. This observed linear relationship was the basis for determination of μ_e using a simple linear fit. The measured signal amplitude was also used to determine μ_eτ_e using the Hecht formulation. Repeated measurements confirmed the consistency of the method in determining μ_e and μ_eτ_e.