Extraction of mean free path of charge carriers in CdZnTe crystals from measured full-energy peaks

The mean free path of electrons (λe) and holes (λh) in a CdZnTe crystal were extracted from measured γ-ray spectra. First, distortion due to Gaussian broadening was unfolded from full-energy peaks in the γ-ray spectra. As a result, only tailing was left in the unfolded peaks. Second, λe and λh were determined by fitting tailing of full-energy peaks in calculated response functions to that in the unfolded γ-ray spectra. The response functions were calculated using EGS4 with the Hecht equation coded. 2.5×102 cm for λe and 5.0×10−2 cm for λh were obtained in an electric field of 2500 V/cm: the μτ products were found to be 1.0×10−1 cm2/V for electrons and 2.0×10−5 cm2/V for holes. This method is reasonable to obtain λe and λh, which are necessary to correct the distortion caused by tailing in X-ray spectra.