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Kamwang, N.*; 古渡 意彦; 吉富 寛
Proceedings of 4th Asian and Oceanic Congress on Radiation Protection (AOCRP-4) (CD-ROM), 4 Pages, 2015/07
For proper implementation of the radiation monitoring, radiation monitoring instruments require to be ensured whether their characteristics meet the criteria for radiological protection uses. This is because the energy response to incident photons varies with energies, which is called "energy dependence". In this study, we focused on the energy dependence for hand-held type survey meters with wide energy range from 45 keV up to 7 MeV. The ionization chamber (IC) type, the geiger-mueller counter (GM) type and the plastic scintillation (PS) type survey meters were engaged. A series of measurement was performed with the narrow series X-ray field, radionuclides gamma-ray fields and the high energy gamma ray field by the 4 MV Van-de-Graaff accelerator. The results show that IC and PS type survey meters have almost uniform energy dependence with the whole energy range between 45 to 6,600 keV. On the other hand, the response of GM type survey meter was deviated to the unity, the responds seems reliable only at the energy between 250 and 1,250 keV.
吉富 寛; 古渡 意彦; 鈴木 隆
Proceedings of 4th Asian and Oceanic Congress on Radiation Protection (AOCRP-4) (CD-ROM), 4 Pages, 2015/07
原子力機構放射線標準施設では、2種類の
線照射システム(BSS2及びJBS)により構築された線標準場を用いて線量計の校正に供している。2つの線照射システムは、線源や線源膜の厚さ、ビームフラッタニングフィルタの有無などが異なっていることから、同一の線源核種によって作られる線標準場であっても線質が異なり、線量計の校正に影響を及ぼす可能性がある。そこで、
Sr/Y及び
Pm標準場について、組織吸収線量率やその組織中深度分布、スペクトル形状の比較を行い、その差異が校正に与える影響について調べた。測定や計算手法の妥当性は、既によく研究がされているBSS2での結果から確認した。その結果、Sr/Y標準場については、400mg/cm
を超える厚みのある線量計や高原子番号の線量計において、Pmについては、薄型の生体等価な線量計においても校正結果に影響を与える可能性があることが明らかになった。
吉富 寛; 谷村 嘉彦*; 立部 洋介; 堤 正博; 川崎 克也; 古渡 意彦; 吉澤 道夫; 清水 滋*; Kim, J.-S.*; Lee, J.-G.*; et al.
Proceedings of 4th Asian and Oceanic Congress on Radiation Protection (AOCRP-4) (CD-ROM), 4 Pages, 2015/07
A series inter-comparison regarding basic quantities of radiation calibration fields and calibration techniques has been made between KAERI and JAEA since 2006. Air kerma rates of the ISO narrow series X-ray calibration fields and neutron spectra at a point of test in each institute and results revealed that KAERI and FRS-JAEA maintained well-defined calibration fields for X-ray and D
O-Cf neutron calibration fields. Intensive calibrations of personal dosimeters in RI neutron calibration fields and beta-ray calibration fields were performed in both institutes. Results of calibration factors indicate that almost identical calibration factors could be obtained.