Performance of an in-situ alpha spectrometer

R. Pöllänen

Applied Radiation and Isotopes, Volume 109, March 2016, Pages 193–197

Proceedings of the 20th International Conference on Radionuclide Metrology and its Applications 8–11 June 2015, Vienna, Austria

Abstract: Equipment was recently developed for detecting alpha particles from flat and smooth surfaces with good energy resolution at ambient air pressure. In this work, the detection efficiencies were determined using different extended-area sources emitting alpha and beta radiation and a mixed nuclide point source emitting alpha radiation. Beta particles are of importance because they can also be detected. Counts originating from alpha and beta particles are mainly at different energies, which make their separation possible. An efficiency of 0.14 was determined for an extended-area (>30 cm2) homogeneous source emitting alpha radiation at the energy of 5–6 MeV, whereas for the beta emitters the efficiencies were 0.07–0.19 depending on the beta-particle emission energies. The use of a collimator reduces the detection efficiencies by a factor of up to ten.