Efficiency calibration of a Ge detector in the 0.1-11.0 MeV region

An efficiency curve was constructed for a large-volume Ge detector located at the thermal-neutron beam line of the JRR-3M reactor at the Japan Atomic Energy Research Institute (JAERI). The calibrations for gamma -ray energies below 2754 keV were accomplished with a large number of radioactive source s and above 2754 keV with the C-12(n,gamma) and N-14(n,gamma) reactions. Th is detector and its efficiency curve were subsequently used to determine ac curately the photon emission probabilities of gamma rays from the decays of Co-56 (T-1/2 = 77 d) and Ga-66 (9.5 h) and from the Cl-35(n,gamma) reactio n. These radiation sources can serve as secondary standards for efficieney calibrations. (C) 2000 Elsevier Science B.V. All rights reserved.