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古田 琢哉; 橋本 慎太郎; 小川 達彦; 谷村 嘉彦
Nuclear Instruments and Methods in Physics Research A, 1086, p.171320_1 - 171320_8, 2026/06
被引用回数：0 パーセンタイル：0.00(Instruments & Instrumentation)物質に対する中性子照射から荷電粒子が放出される反応において、放出粒子と特定の励起状態にある残留核を同時に扱う核データライブラリを組み込むための新機能を、モンテカルロシミュレーションコードである 粒子・重イオン輸送計算コードPHITSに実装した。本機能により、残留核の生成および脱励起ガンマ線の放出を考慮しつつ、各事象における全エネルギーおよび運動量保存を満たした上で、核データライブラリに基づく放出粒子のエネルギースペクトルおよび角度分布の高精度な予測が可能となる。この機能を用いることで、検出器応答や材料中の放射線損傷の高精度シミュレーションが実施できる。
Ba 
-ray calibration field for photon energy in the 300-400 keV range辻 智也; 吉富 寛; 古渡 意彦*; 佐藤 文信*; 谷村 嘉彦
Radiation Protection Dosimetry, 202(8), p.619 - 630, 2026/05
被引用回数：0 パーセンタイル：0.00(Environmental Sciences)A -ray calibration field using a sealed Ba source for photon energy in the 300 - 400 keV range was established at the Japan Atomic Energy Agency to evaluate radiation protection devices under low dose rate conditions. To suppress low-energy -ray components, a 2-mm lead filter was applied. The photon fluence spectrum was measured using a CdTe spectrometer and an unfolding method, yielding a spectrum with a mean energy of 321 keV. Reference air kerma rates were determined using ionization chambers calibrated in a 
Cs field, with energy correction factors applied. Spectrometry using a CeBr
scintillation spectrometer combined with the G(E) function method was employed to validate these corrections. Spectrum-averaged conversion coefficients were derived from the measured spectrum, indicating equivalence to the N-400 radiation quality. This field provided air kerma rates from 0.22 to 2.13 
Gy h
, suitable for testing devices used in environmental monitoring and nuclear emergency response.
辻 智也; 吉富 寛; 佐藤 文信*; 谷村 嘉彦
Radioisotopes, 75(S-01), p.S-004_1 - S-004_6, 2026/04
Radiation dosimeters must be well calibrated and tested according to international standards. In the ISO 4037:2019 standard series, requirements regarding photon calibration fields to be used are clearly specified. The X-ray narrow-spectrum series (N-series) calibration field is commonly used to test energy response of dosimeters. Thus, we established an N-series calibration field using a soft X-ray generator, YXLON MG165/4.5, at the Facility of Radiation Standards (FRS) of Japan Atomic Energy Agency (JAEA). The radiation quality of an X-ray calibration field is characterized by the following parameters: mean energy of a beam, resolution of X-ray spectral fluence, half-value layer (HVL) of Al or Cu filters with respect to air kerma and homogeneity coefficient. The established calibration fields were verified to ensure that these parameters were in accordance with the recommendations of the ISO 4037-1:2019 based on measurements.
谷村 嘉彦
放計協ニュース, (76), p.2 - 6, 2025/10
放射線標準施設棟(FRS)は、放射線管理で広く用いられているサーベイメータ、線量計などの放射線測定器の特性試験や校正を行うための施設であり、利用できる放射線の種類、エネルギー範囲、品質において世界でもトップレベルの試験・校正施設である。FRSは、1980年に誕生し、本稿の執筆時には45年の節目の年になっている。この機会に誕生当初の状況、設備の拡充やJIS試験所登録など、FRSがこれまでに歩んできた歴史を振り返るとともに、これからの展望についてまとめる。
辻 智也; 吉富 寛; 西野 翔; 佐藤 文信*; 谷村 嘉彦
Journal of Radiological Protection, 45(3), p.031519_1 - 031519_8, 2025/09
被引用回数：0 パーセンタイル：0.00(Environmental Sciences)In response to the new operational quantities proposed in ICRU Report 95, we calculated conversion coefficients for high monoenergetic photon calibration fields-specifically, the 
Am -ray calibration field and the fluorescence X-ray calibration field-both of which are listed in the annex of the ISO 4037 standard series. These coefficients were derived using measured photon spectral fluence. Additionally, correction factors for air density were determined for the low-energy fluorescence X-ray calibration field. Both the conversion coefficients and the air density correction factors were found to vary within the standard uncertainty specified by the ISO 4037 series.
辻 智也; 吉富 寛; 佐藤 文信*; 谷村 嘉彦
Radiation Protection Dosimetry, 201(9), p.648 - 662, 2025/06
被引用回数：2 パーセンタイル：77.30(Environmental Sciences)An irradiation environment for dosemeters calibration in the fluorescence X-ray field was set up at the Facility of Radiation Standards of the Japan Atomic Energy Agency (JAEA) by re-establishing the fluorescence X-ray calibration field that was established in 1989. The reference air kerma rates were determined using reference ionization chambers (ICs) calibrated using X-ray narrow-spectrum series calibration field of the national metrology standard (NMS) in Japan. Since no X-ray calibration field using fluorescence X-rays is available in Japan, the measurements were corrected by factors that accounts for differences in the fluorescence X-ray calibration field energy and the X-ray narrow-spectrum series calibration field energy. The conversion coefficients and correction factors for air densities for the fluorescence X-ray calibration field, including those unavailable in the ISO 4037 standard series, were derived from the measured X-ray fluence rate spectra.
古渡 意彦*; 吉富 寛; 谷 幸太郎*; 谷村 嘉彦; 栗原 治*
Radiation Protection Dosimetry, 200(16-18), p.1574 - 1579, 2024/11
被引用回数：0 パーセンタイル：0.00(Environmental Sciences)This study attempted the reconstruction of organ doses of victims who are highly exposed to gamma rays in non-homogeneous exposure accident by a sealed 
Ir source in Gilan, Iran. According to the accident report by International Atomic Energy Agency (IAEA), a victim was highly exposed on his right chest and the dose estimation by means of biodosimtry and clinical observation were carried out. However, dose reconstruction by means of physical dosimetry was not completely made. In this study, a series of Monte Carlo (MC) calculations employing the PHITS 3.24 incorporated with the Adult male Mesh-type Reference Computational Phantom was performed to estimate organ doses with reference to an actual radiation accident involved in the Ir sealed source, and to investigate issues on reconstruction of organ doses of victims who are highly exposed to radiation under non-homogeneous exposure accident. Calculated organ doses for the lungs, the red born marrow, and the small intestine by MC calculation were compared with experimental values taken from the literature and were within 23% in terms of mGy h /Ci for the Gilan case. The averaged whole body dose was estimated to be 0.31 Gy, which are less than one-tenth than that estimated by biodosimetry (3.1-4.1 Gy). In the IAEA Gilan report, the average whole body dose was assumed to be 2 Gy for rough estimation of physical dose, having a large discrepancy with those estimated by the MC calculation.
石井 隼也*; 清水 森人*; 加藤 昌弘*; 黒澤 忠弘*; 辻 智也; 吉富 寛; 谷村 嘉彦; 渡部 浩司*
Journal of Radiological Protection, 44(3), p.031516_1 - 031516_8, 2024/09
被引用回数：0 パーセンタイル：0.00(Environmental Sciences)The dosimeter response should be calibrated in a reference field near the user's radiation environment. Environments around nuclear reactors and radiation therapy facilities have high-energy photons with energies exceeding that of 
Co gamma rays, and controlling exposure to these photons is important. The Japan Atomic Energy Agency (JAEA) and National Metrology Institute of Japan (NMIJ) have high-energy reference fields with energies above several MeV for different types of accelerators. Their reference fields have different fluence-energy distributions. In this study, the energy dependencies of the two-cavity ionization chambers, which are often used by secondary laboratories, were experimentally and computationally evaluated for each high-energy field. These results agreed well with relative expanded uncertainties (
= 2), and their capabilities for air kerma measurements in each high-energy reference field were confirmed. Therefore, the capabilities of the air-kerma measurements can be verified in the two high-energy reference fields.
Am gamma calibration field based on international standards and its conversion coefficients辻 智也; 吉富 寛; 古渡 意彦*; 谷村 嘉彦
Radiation Protection Dosimetry, 200(15), p.1416 - 1424, 2024/09
被引用回数：4 パーセンタイル：57.90(Environmental Sciences)A Am gamma ()-ray calibration field that meets the requirements for a -ray reference field as specified in the ISO 4037 standard series was established in the Facility of Radiation Standards of the Japan Atomic Energy Agency. The reference air kerma rates were measured using a reference ionization chamber (IC) calibrated by the N-80 quality X-ray calibration field of the national metrology standard in Japan and with a correction to account for differences in photon energy due to the calibration field. Conversion coefficients for the Am -ray calibration field, including those not listed in the ISO 4037 standard series, were calculated based on the measured -ray fluence rate spectra.
谷村 嘉彦; 吉富 寛; 西野 翔; 辻 智也; 深見 智代; 篠塚 友輝; 大石 皓平; 石井 雅人; 高宮 圭; 大貫 孝哉; et al.
Radiation Measurements, 176, p.107196_1 - 107196_6, 2024/08
被引用回数：1 パーセンタイル：22.05(Nuclear Science & Technology)ICRUはReport95で場や個人被ばくのモニタリングに用いる実用量の定義を変更した。新しい実用量を導入した場合に、さまざまな原子力施設の作業現場における線量測定に影響する。このため、作業場のエネルギースペクトルや測定器の特性を把握しておく必要がある。本研究では、原子力機構にある研究炉(JRR-3)及び加速器施設(J-PARC)の作業場において、NaI(Tl)又はLaBr
(Ce)シンチレーション検出器を用いて光子スペクトルを測定した。そして、現行及び新しい実用量を導出してこれらを比較した。
谷村 嘉彦; 吉富 寛
日本原子力学会誌ATOMO
, 66(1), p.42 - 45, 2024/01
放射性同位元素の規制等に係る法律改正により、RI施設における放射線測定の信頼性確保が法令で要求されており、その基盤となる放射線測定器の校正や試験を行う標準場の品質保証が重要となっている。本稿では、国立研究開発法人日本原子力研究開発機構の放射線標準施設棟に整備されているX線、線、
線及び中性子線の各種二次標準場の現状と今後の展開について概説する。また、放射線分野で初となるJIS登録試験所で提供できる試験サービスの内容、放射線標準場に関する国際規格(ISO規格)の最新動向について解説する。
横山 須美*; 立崎 英夫*; 谷村 嘉彦; 吉富 寛; 平尾 茂一*; 青木 克憲; 立木 秀一*; 江崎 巌*; 星 勝也; 辻村 憲雄
Journal of Radiological Protection, 42(3), p.031504_1 - 031504_17, 2022/09
被引用回数：3 パーセンタイル：31.19(Environmental Sciences)日本では、2021年4月に水晶体の等価線量限度が改定された。その結果、眼の水晶体の線量限度と実効線量の線量限度が等しくなった。放射線作業者,放射線安全管理者,免許取得者は、放射線防護に関連する規制を遵守し、防護を最適化する必要がある。日本保健物理学会が新たに開発した水晶体の線量モニタリングガイドラインでは、水晶体の線量が管理基準に近づいたり超えたりした場合、正確な推定のために目の近くで線量を測定することを推奨している。しかし、原子力発電所従事者の不均一な被ばくに関する情報は限られている。本研究では、日本の4つの商業用原子力発電所(RWR: 3基,BWR: 3基)において、高線量率作業場の線量当量および88名の作業員の個人線量を測定し、作業員の不均一な被ばくを分析した。
谷村 嘉彦
FBNews, (548), p.1 - 5, 2022/08
原子力災害発生時においては、多数の住民・作業者を対象とした甲状腺ヨウ素モニタリングを、事故後速やかに実施する必要がある。日本原子力研究開発機構では、災害時の高バックグラウンド線量率下でも使用可能な小型で取り扱いが容易な遮蔽一体型甲状腺モニタの開発を行っている。開発した甲状腺モニタシステムの概要及び放射線標準施設棟の線標準校正場等で実施した性能試験から得られた結果を報告する。
古渡 意彦*; 永元 啓介*; 中上 晃一*; 谷村 嘉彦; 盛武 敬*; 欅田 尚樹*
Journal of Radiation Protection and Research, 47(1), p.39 - 49, 2022/03
For proper monitoring of the eye lens dose, an appropriate calibration factor of a dosimeter and information about the mean energies of X-rays are indispensable. The scattered X-ray energy spectra should be well characterized in medical practices where eye lenses of medical staffs might be high. Scattered X-ray energy spectra were experimentally derived for three different types of X-ray diagnostic and therapeutic equipment. A commercially available CdZnTe (CZT) spectrometer with a lead collimator was employed for the measurement of scattered X-rays. From the obtained energy spectra, the mean energies of the scattered X-rays lied between 40 and 60 keV. This also agreed with that obtained by the conventional half value layer method. The obtained mean energies of the scattered X-rays were found to match the flat region of the dosimeter response.
古渡 意彦; 谷村 嘉彦; Kessler, P.*; Neumaier, S.*; R
ttger, A.*
Radioisotopes, 70(1), p.1 - 18, 2021/01
For proper environmental radiation monitoring, a method to simultaneously determine ambient dose equivalent rate and radioactivity concentration in the air by using a newly developed scintillation spectrometer, namely a CeBr spectrometer was investigated. The performance of the proposed method, including energy dependence and linearity of the spectrometer, was verified by a series of measurements, conducted according to the procedure of inter-comparison of detectors used for early warning network performed by the European Radiation Dosimetry Group (EURADOS). Measurement results show that the proposed method is suitable for environmental monitoring purposes. After thorough tests, the activity concentration in air was determined in the laboratory by using a point-like sealed Ba source to mimic a radioactive cloud containing 
I and Xe. The photon fluence rate was obtained from the pulse height distribution by using the unfolding method, and the activity concentration in air for radioisotopes of interest, mainly Xe, was estimated from the obtained photon fluence rate by applying the conversion coefficient evaluated via a Monte Carlo calculation. The results additionally show that the method presented in this study is reliable and suitable for the environmental radiation measurement.
Sr+Y beta field; Full-face mask respirator shielding and dosemeter positioning辻村 憲雄; 星 勝也; 山崎 巧; 百瀬 琢麿; 青木 克憲; 吉富 寛; 谷村 嘉彦; 横山 須美*
KEK Proceedings 2020-5, p.21 - 28, 2020/11
To investigate the shielding effects of full-face respirator masks and the suitable positioning of lens dosemeters, irradiation experiments of Sr+Y beta particles were performed using an anthropomorphic head phantom into the eyes of which small thermoluminescence dosemeters (TLDs) were loaded, and the lens doses measured by these TLDs were compared with the doses measured by commercially available personal dosemeters attached around the eyes of the phantom. The three tested masks reduced the beta lens dose to 9-14% as compared to the lens doses in the absence of a mask. As for the suitable positioning of lens dosemeters, the 
(0.07) evaluated by the (0.07) dosemeter attached at the center of the forehead gave an over-response to the lens dose by a factor of 2.5-8.4 regardless of the presence of masks. The (3) evaluated by the (3) dosemeters, even though placed at extreme positions near the outside corners of the eyes, provided better lens dose estimates with a response of 0.38-1.7.
scintillation spectrometer due to terrestrial gamma ray components; Application in environmental radiation monitoring古渡 意彦; 谷村 嘉彦; Kessler, P.*; Rttger, A.*
Radiation Measurements, 138, p.106431_1 - 106431_6, 2020/11
被引用回数：1 パーセンタイル：7.19(Nuclear Science & Technology)In radiological emergency, timely and reliable radiological information such as dose rate or radioactive concentrations due to artificial radionuclides is indispensable to protect general public and the first responder of the situation. The authors have investigated the method for effectively identifying and determining the radioactivity concentration using a scintillation spectrometer. In this study, the authors demonstrate how influence of terrestrial background (BG) component on measured pulse height spectrum can be minimized to obtain the peaks from gamma rays emitted by artificial radioactivity. In some cases of radiological emergency monitoring, subtraction of BG components was probe to be difficult, because the prior measurement of BG component at the place to be monitored is compulsory. By removing the BG component appropriately from measured pulse height spectrum without any prior BG measurement, the effective minimum detection limit of the spectrometer would be declined.
横山 須美*; 江崎 巌*; 立崎 英夫*; 立木 秀一*; 平尾 茂一*; 青木 克憲; 谷村 嘉彦; 星 勝也; 吉富 寛; 辻村 憲雄
Radiation Measurements, 138, p.106399_1 - 106399_5, 2020/11
被引用回数：4 パーセンタイル：30.29(Nuclear Science & Technology)In Japan, the possibility to change the current dose limit of the lens of the eye for the radiation workers working in the planned exposure situation (normal controlled situations) to a new ICRP dose limit was discussed. It was further discussed how to appropriately monitor and manage the equivalent dose of the eye lenses for these workers exposed to radiation at their workplaces, such as nuclear and medical facilities. Among the workers exposed to a high-dose radiation at the water storage flange tank deconstructed Sr/Y dominant areas and the nuclear reactor buildings (high dose gamma-ray) of the Fukushima Daiichi Nuclear Power Plant (1F-NPP), H
(10), H(3), and H(0.07) at the head and the chest (or the upper arm) were estimated by passive personal dosimeters using thermoluminescence dosimeters (TLDs) and radio photoluminescence glass dosimeters (RPLGDs). The relationship between H(10), H(3), and H(0.07) along with the effects of the sites of wearing dosimeters on the head inside a full-face mask and the chest (or upper arm) were discussed.
谷村 嘉彦; 吉富 寛; 西野 翔; 高橋 聖
Radiation Measurements, 137, p.106389_1 - 106389_5, 2020/09
被引用回数：0 パーセンタイル：0.00(Nuclear Science & Technology)日本原子力研究開発機構では、原子力施設での事故等の高バックグラウンド線量率下において、公衆及び作業者の甲状腺の内部被ばく線量を測定するために、線スペクトロメータを用いたエネルギー分析型甲状腺放射性ヨウ素モニタを開発している。本稿では、円柱型PMMAファントムを用いたバックグラウンド放射線の補正方法について報告する。
星 勝也; 吉富 寛; 青木 克憲; 谷村 嘉彦; 辻村 憲雄; 横山 須美*
Radiation Measurements, 134, p.106304_1 - 106304_5, 2020/06
被引用回数：4 パーセンタイル：30.29(Nuclear Science & Technology)原子力規制庁の放射線安全規制研究戦略的推進事業において採択された「原子力・医療従事者等の標準的な水晶体の等価線量モニタリング、適切な管理・防護はどうあるべきか?水晶体被ばくの実態から探る」の一部である。本研究は2つのフェーズからなり、第一に光子に対する個人線量計の特性に関する実験室での照射試験、第二に福島第一原子力発電所の実際の作業環境で実施されたフィールド試験である。本稿は前者の研究結果について報告するものである。発電所において使用される全面マスクの遮へい効果及び線量計の装着位置依存性を明らかにするため、人体形状を精密に模擬したファントムの頭部に、水晶体線量評価用の線量計を装着し、ガンマ線及びエックス線校正場において照射試験を実施した。頭部に装着した個人線量計の指示値は、換算係数から計算される理論的な水晶体等価線量の
20%以内に一致しており、取り付け位置の違いによる差は小さいことが確認された。また、照射した光子エネルギー範囲(83
662keV)において、全面マスクの遮へい効果はほとんど期待できないことが分かった。
