A Low Level Beta Scintillation Counter

An automatic scintillation counter for the measurement of low beta activity samples is described. Background is in the order of one (1) count per minute. Efficiency of counting for K-40 betas is thirty (30) per cent. The scintillator is a thin plastic phosphor mounted on the sample which makes a simple, rugged package suitable for automatic sample changing. Photomultiplier tube noise measurements, preamplifier circuit, and the mechanical details are discussed.