Evaluation of Detection Characteristics for Ge Scanning-Type Whole-Body Counter by Monte-Carlo Simulation

None

栗原 治; 高崎 浩司  ; 百瀬 琢麿  ; 寺門 義則*; 高橋 幸嗣*

Kurihara, Osamu; Takasaki, Koji; Momose, Takumaro; Terakado, Yoshinori*; Takahashi, Koji*

内部被ばく線量評価技術の高度化の為、可動型のゲルマニウム半導体検出器を有する全身カウンタスキャニング型全身カウンタ)を開発した。本発表では、同機器の検出特性をモンテカルロシミュレーションコードMCNP-4Cによって検証し、計数効率において実験値と非常に良い一致を見た。

As an alternative to the phantom used for calibrating whole-body counters, in this study the Monte Carlo simulation was used to evaluate peak efficiencies for a whole-body counter installed at the JNC, to examine the validity of using the simulation technique to calibrate the whole-body counter. Prior to simulating a phantom, the sensitive region of the crystal in the Ge detectors which are used with the whole-body counter, was evaluated by assuming dead layers in the simulation. The phantom was then simulated based on the determined configuration of the sensitive region. As a result, the calculated peak efficiencies were fairly consistent with the measured ones. For an entire body scanning measurement, the discrepancy between the measurement and the simulation was within 4% for peak energies ranging from 81.0 keV to 1460.8 keV. The simulation technique is therefore both effective and practical for situations that are difficult to be simulated by a phantom.