CORRECTION OF INCOMPLETE CHARGE COLLECTION IN CDTE DETECTORS

The characteristic of incomplete charge collection for several types of planar CdTe spectrometers has been studied both theoretically and experimentally. The aim was to develop a theoretical function for correcting the incomplete charge collection by correlating the charge collected with the position of interaction. We studied the dependence of this function on various parameters which characterize the crystal. Monte-Carlo calculations using the MCNP code were incorporated with a model function which included trapping and detrapping of the created charge. The calculations were utilized to determine the charge distribution and the risetime distribution for different detectors and irradiation configurations and for several photon energies. The charge correction function was correlated with experimental data to extract crystal parameters. It is shown that the correction function is useful when the detectors are operated at high electric fields where applying this function to experimental data improves the energy spectra significantly.