Investigation of charge collection properties of CdTe detectors by optical pulses

The performances of radiation detectors based on semiconductor compounds are strongly affected by the incomplete charge collection of the photo-generated carriers. In order to investigate how different causes such as trapping or material inhomogeneities affect the signal formation, a technique is required which can gain access to the local charge collection properties of the detector. To this scope it has been assembled an experimental set-up able to detect charge transients induced by infrared pulses and it has been tested on a multi-strip CdTe detector. The implemented technique appears as a powerful and inexpensive tool for the characterization and optimization of single and multi-element detectors.