Thin film techniques for developing a more rugged alpha scintillation detector

The objective of this project was to develop an alpha scintillation detector more rugged than conventional detectors having aluminized Mylar entrance windows, which can be damaged in some hostile environments encountered in field surveys. A more durable, light- tight entrance window will reduce maintenance costs. This developmental model consists of a thin sandwich of scintillator, opaque material, and scuff-resistant coating deposited on a transparent substrate. Several scintillators have been evaluated for light output and high alpha-to-gamma ratio. After optimizing the thickness of the scintillator, the layer is made opaque to ambient light by coating the front side with a light-tight material such as aluminum. The opaque entrance window is protected with a scuff-resistant layer of silicon dioxide, and the finished wafer is attached to a photomultiplier tube to complete the detector assembly. 6 refs., 7 figs.