Abstract
A description is given of a simple type 4π β-scintillation counter which consists of a single 13 stage photomultiplier tube and two thin (similar 1·3 mm thick, 2·5 cm square) plastic scintillators having sources mounted between them, operated at −25°C. The characteristics of the instrument are discussed and resulsts of intercomparisons of measurements of solutions of several radio nuclides by this and a 4π Geiger β-counting technique are reported. It is concluded that the method is satisfactory for the absolute measurement of β-emitters of maximum energy similar 0·5 MeV and above, although the accuracy attained is unlikely to exceed that possible using 4π Geiger and proportional counting techniques. It is noted that the comparative simplicity of the method should prove an advantage where highest accuracy in such measurements is not required.