Event classification in 3D position sensitive semiconductor detectors

A set of analytical methods for pixelated 3D position sensitive semiconductor detectors has been developed to make better measurements of gamma-rays in the 30 keV to 3 MeV energy range. The ability to classify pixel charge sharing, x-ray escape, pair production, and Compton scattering allows for more accurate and efficient energy reconstruction and Compton imaging routines. The techniques are based on the analysis of digitized preamplifier waveforms from the electrodes that sense charge following an interaction. Accurate identification of an event is based on the comparison of an expected detector response with precise measurements of an interaction’s resulting signal amplitude, shape, and timing characteristics. A tungsten collimator is used to demonstrate the accuracy of the classification methods. Experimental results taken with large volume CZT and HgI2 detectors are compared with system simulations.