Investigations on TDCR measurements with the HIDEX 300 SL using a free parameter model

The Triple to Double Coincidence Ratio (TDCR) method requires a special counting system with three photodetectors. The systems currently used by National Metrology Institutes for activity standardizations are custom built, and up to now the HIDEX 300 SL counter1,2 is the only TDCR counter commercially available.At PTB, measurements with a special metrology version of this counter were carried out to investigate its applicability for activity standardizations. The activity results of measurements with the HIDEX counter are compared to those obtained with a PTB–TDCR counter, as such a comparison reduces the model dependence. In addition, a spectrometry method was applied to measure 109Cd samples and a new TDCR-Čerenkov method was tested with 32P samples.

► A special metrology version of a commercial TDCR counter from Hidex Oy has been tested. ► PMT threshold adjustment and the setting of the coincidence resolving time are discussed. ► Results were in reasonable agreement with those obtained by a PTB–TDCR counter. ► A spectrometry method was successfully applied to measure 109Cd samples. ► Hidex counter was also used to apply a new TDCR-Čerenkov method.