High Yield Growth and Fabrication of Spectroscopic Radiation Detection Semiconductors

High energy resolution is a key performance metric of radiation detectors which determines the accuracy and speed of radioactive nuclide identification. CdZnTe (CZT) radiation detectors are currently the only commercially available room temperature semiconductor detectors, with their superior spectral resolution approaching performance of cooled High Purity Germanium detectors. The persistently high price and the very slow increase in the size of these detectors have limited the deployment of radiation detection instruments based on this detector. Under this program, we will develop technology for crystal growth and fabrication of gamma radiation detectors based on an emerging class of new materials, the perovskites. Perovskite detectors have already shown very high and promising energy resolution rapidly approaching that of CZT detectors. Perovskite crystals, however, offer the potential of significantly lower production cost and higher yield of superior detector materials. In Phase of this program, we improved the crystalline quality and chemical purity of the perovskite semiconductor crystals and obtained detectors with high charge collection properties and superior spectroscopic response approaching those of CZT. The detectors performed well under high radiation fluxes and we developed approaches to improve their long term stability. In Phase II we will focus on implementing new technologies to eliminate crystalline defects in the crystals, eliminate polarization effects and have the fabricated detectors evaluated by two leading commercial vendors of radiation detection instruments. The high-resolution radiation detectors to be developed in this program have application in homeland security, nuclear stockpile monitoring, nuclear contamination monitoring, and nuclear plant monitoring. There is also increasing demand from the military to equip military vehicles with these types of detectors. In the medical imaging area, there is a rising demand for high resolution detectors for SPECT, bone mineral densitometry, surgical probes and multi-color photon counting computed tomography.