LCSガンマ線源を使用したビーム形状における同軸HPGe検出器の効率の評価

Evaluating coaxial HPGe detector efficiency in beam geometry using LCS -ray source

Omer, M.  ; 静間 俊行*; 羽島 良一*; 小泉 光生 ; 平 義隆*

Omer, M.; Shizuma, Toshiyuki*; Hajima, Ryoichi*; Koizumi, Mitsuo; Taira, Yoshitaka*

High-resolution -ray spectroscopy involving beam geometry may be measured with higher efficiency if -ray beam hits out of the axis of the coaxial HPGe detector. Hitting off-axis makes -rays avoid travelling through the contact hole, which is an inactive axial portion of the detector. We performed Monte Carlo simulations to study the effects of contact hole dimensions and off-axis distance on the coaxial HPGe detector efficiency. The simulation considered -ray energy up to 10 MeV. In general, the simulation results reveal that the off-axis efficiency is higher than on-axis efficiency for a wide range of -ray energies and beams sizes. Our simulations results are validated by experimental measurements of -ray beams generated from laser Compton scattering at UVSOR III facility.