Cerenkov counting as a complement to liquid scintillation counting

A commercially available spectrometer was calibrated for liquid scintillation (LS) and Cerenkov counting efficiency (CCE) using National Institute of Standards and Technology traceable solutions. The CCE increased linearly over a 3 order of magnitude range in K-40 beta activity, and by 42% per MeV as beta-energies increased from 0.300 to 3.54 MeV, achieving a maximum value of 80% for Ru-106/Rh-106. The CCE can be enhanced by 10-15% when a wavelength shifter is used. A comparison of the data showed that the CCE was typically 20-50% less than the LS counting efficiency for beta-particles with maximum energies >1 MeV. Applications that utilize sequential CCE and LS counting to quantitate activity concentrations are discussed for samples containing two beta-emitting nuclides of differing energies. Published by Elsevier Science Ltd