Activity standardization by means of a new TDCR-Čerenkov counting technique

Samples containing high-energy beta emitters in hydrochloric acid were measured in an in-house built triple-to-double coincidence counter. For the analysis of the results, a new method was developed that is based on a free parameter model. Formulas for the determination of the counting efficiencies were derived assuming a Poisson distribution for the generation of photoelectrons at the photocathodes and applying the Frank and Tamm theory to the production of Čerenkov light. The anisotropy effect for the emission of Čerenkov light was taken into account. The activities determined with the new method were compared with the results from other primary standardization techniques. The following radionuclides were successfully studied: 32P, 89Sr, 90Y, 204Tl and 106Rh.