Application of a Ge semi-conductor detector to whole-body counter

Kinase, Sakae   ; Noguchi, Hiroshi; Nakamura, Takashi*

To calibrate a whole-body counter, it is necessary to find a determination method for peak efficiencies of detectors that the whole-body counter has. For the purpose, peak efficiencies of a Ge semi-conductor detector for point sources and volume sources were evaluated in the photon energy range of 60-1,836 keV by Monte Carlo simulation and experiment. It was found that the calculated peak efficiency curves as a function of energy without modeling the actual sensitive region of the detector are similar in shape to those measured. The calculated peak efficiencies of the detector that has an apparent dead layer (1mm) were also found to agree with the experimental values. Consequently, the simulation method for peak efficiencies was validated. In addition, an optimum design for a whole-body counter with Ge semi-conductor detectors was examined by simulation. This simulation enables to provide a method to determine an optimum arrangement of detectors in a whole-body counter offering a uniform response to various Cs-137 distributions in a human body.