| Event-by-event classification of 30 keV to 3 MeV photon interactions in pixelated CZT and HgI2 detectors has been achieved through analysis of preamplifier output waveforms. The methods rely on analysis of the digitized waveforms sampled at 100 MSa/s from charge collecting pixels, pixels that neighbor charge collecting pixels, and the cathode. Digital signal processing methods have been developed and optimized to measure the range of signal features found in the pulse waveforms. Precise measurements of these features enable detection of the signatures of photoelectric absorption, Compton scattering, characteristic X-ray escape, pair production, and charge sharing events. Experimental data from a digital readout system is used to demonstrate the value of event classification in improving energy resolution and radiation interaction position. Simulation and experimental validation techniques demonstrate the accuracy of the event classification methods. The accuracy of the methods ranged between 12 and 99 percent depending on the interaction type and validation method used. |
