SBIR Phase I:High Temperature High Resolution Cesium-Antimony Semiconductor Gamma Spectroscopy Detectors for Borehole Radiochemical Analysis

This Small Business Innovation Research Phase I Project aims to construct a novel elevated temperature gamma ray spectroscopy detector for borehole nuclear geochemistry. Cesium-Antimony (Cs3Sb) is a semiconductor widely used commercially for thin film vacuum photocathodes. In single crystal form, it has many properties superior to Ge for gamma radiation detection: (1) a lower electron-hole pair energy (2 eV vs 3 eV) for better intrinsic energy resolution; (2) a higher bandgap (1.6 vs 0.7 eV) for low thermal noise, even lower than CdTe and operation at room or elevated temperatures; and (3) a higher Z (55 & 51, vs 32) for a stopping power 4-5 times greater ~ MeV gamma rays. In Phase I, the aim is to grow sufficiently large crystals of Cs3Sb, and fabricate them into environmentally (oxygen, water vapor) protected room temperature radiation detectors, to demonstrate that they may become the future of gamma ray detectors. These detectors could replace NaI(Tl) and other scintillator detectors, and SiLi and HPGe gamma ray spectroscopy detectors in industrial and medical analytical instrumentation. This development will enable new scientific instrumentation used in research and education in chemistry, physics, planetary science, astrophysics, biology, medicine and other places where x- and gamma- rays are used. The results will be widely disseminated and published.