Activity determination of ⁵⁶Mn using extended TDCR-Čerenkov method

The accuracy of activity determination for activated nuclide ⁵⁶Mn is the key to the manganese bath method applying to the characterization of radionuclide neutron source. As an alternative to the 4π(Č)-γ method, TDCR-Čerenkov method could also be applied to the measurement of ⁵⁶Mn in the manganese bath device, if the existing calculation model is extended. There are two difficulties when the existing TDCR-Čerenkov method is applied to the activity determination of ⁵⁶Mn. One is that the efficiency computation of gamma transitions, and the other is the interference contributed by Čerenkov photons emitted in the photomultiplier windows induced by Compton scattering. In this study, the above two difficulties are solved by extending the calculation model. For efficiency computation, the decay scheme of ⁵⁶Mn is taken into account in the calculation of efficiency. Among them, the efficiency of gamma transition is calculated from the simulated secondary electronic spectra. In addition, Čerenkov photons emitted in photomultiplier windows are corrected by additional light proof experiment and improved calculation model. The results derived from this extended method are in good agreement with other standardization technique.