High Efficiency Semiconductors for Nuclear Detection

There is a need for low cost, high performance gamma-ray detectors for national and homeland security applications for detection, identification and localization of special nuclear materials. Common detectors used in this application include scintillators coupled to photomultiplier tubes or silicon photodiodes, and semiconductor detectors like cadmium zinc telluride. Semiconductor detector offer better energy resolution, lower power requirements and smaller size. However, despite decades of research and development the cost of CZT detectors remains high. To meet the needs of nuclear security a lower cost alternative with better properties is desirable. In recently there have been significant advances in heavy metal compound semiconductor halides like cesium lead perovskite and thallium bromide. There are numerous other semiconductor materials with the appropriate properties that may offer improved gamma-ray stopping power, lower noise and better energy resolution. In this effort, we will study and compare at least four new high atomic number materials selected based on average atomic number and semiconductor  bandgap. We will develop synthesis and crystal growth techniques, and fabricate and characterize detectors from each. Testing will be focused on sensitivity and spectroscopy. Based in the detection properties, the most promising material will be selected for further development and optimization Phase II.