Correlation of nuclear spectrometer performance with uniformity and resistivity in cadmium zinc telluride

We have used low-temperature photoluminescence (PL) spectroscopy and room-temperature photoluminescence mapping as a measure of composition variation in cadmium zinc telluride grown by high-pressure Bridgman. We have correlated the uniformity, as measured by the line width of the bound exciton peak in the low-temperature spectrum and the degree of variation in the peak position in the room-temperature map, with the peak-to-valley ratio of the 59.5 keV photopeak in the pulse-height spectrum of ²⁴¹Am. For detectors having active areas of 10-30 mm², the PL measurements can be combined with resistivity measurements to give a strong predictor of detector performance. For arrays of 1 mm² detectors, the correlation between these material parameters and detector performance is much weaker. Our measurements show that material parameters and detector performance can vary substantially between points on a 1 cm sample