A ruggedized ZnS(Ag)/epoxy alpha scintillation detector

An alpha scintillation survey instrument has been developed which is more rugged and efficient than conventional alpha scintillation detectors that use aluminized Mylar ∗∗∗∗Mylar is a trademark of E.I. du Pont de Nemours & Co., Inc., Wilmington, DE, USA. radiation entrance windows. This new detector consists of a mixture of ZnS(Ag) phosphor and optically transparent epoxy. The scintillator mixture is poured into a preformed mold to provide a thin layer of phosphor after the particles settle to the clear epoxy surface. After partial curing, an optically transparent light pipe is coupled to the ZnS(Ag)/epoxy film by using an additional thin epoxy layer, forming a monolithic scintillator assembly. Experimental results indicate that the new probe is 44% efficient (2π) for a large-area 239Pu alpha source; resistant to scratches, tears, and corrosives; watertight; and temperature independent between −20°C and 54°C.