Monte Carlo efficiency transfer method for full energy peak efficiency calibration of three type HPGe detectors: A coaxial N-type, a coaxial P-type and four BEGe detectors

Monte Carlo efficiency transfer method was used to determine full energy peak efficiency of three type high-purity germanium (HPGe) detectors: a coaxial N-type, a coaxial P-type and four broad energy germanium detectors (BEGe). The comparisons between calculations and point source experiments showed that the relative deviations were mostly within ±5% for BEGe detectors in the energy range 13.9–1332 keV, within ±3% for the coaxial N-type detector in the energy range 17.5–662 keV, and within ±3% for the coaxial P-type detector in the energy range 59.5–1332 keV, respectively. An evaluation of Monte Carlo efficiency transfer method at different source-to-detector geometry configurations indicates that peak efficiency may be underestimated when point sources are placed nearer than the reference position to detector on the detector axis, and may be overestimated when point sources are placed far from the detector axis, especially for low-energy photons. Some discussions about direct Monte Carlo calculation method and Monte Carlo efficiency transfer method for full-energy peak efficiency calculation are also presented in this paper.