The SPA38, complete scintillation detector assembly includes our SDA38, NaI(Tl) scintillation detector, a 3 ft BNC cable, a 3ft MHV cable, a 10 position sample stand, a lead shield, and a sample tray. The SDA38, sodium iodide (NaI) scintillator is primarily used for detecting low levels of gamma radiation. It consists of 1.5 in. x 1.5 in. (38.1 mm x 38.1 mm – diameter x thickness), NaI crystal coupled to a photomultiplier tube.