Abstract
A phoswich detector with Compton suppression capability has been developed and assembled for measuring low concentration of xenon radioisotopes in the atmosphere. The phoswich detector has been designed with three scintillation layers. Beta-gamma coincidence events from radioxenon isotopes are identified when a coincidence energy absorption is detected from the first (BC-400) and second (CsI(Tl) crystal) scintillation layers. To identify and reject scattered photons from CsI(Tl) crystal, the crystal is surrounded by a BGO scintillation layer. In this paper, detector assembly steps and our recent measurements with lab sources and radioxenon isotopes produced in the Oregon State University's TRIGA reactor will be discussed.