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-ray fields冠城 雅晃; 鎌田 圭*; 石井 隼也*; 松本 哲郎*; 真鍋 征也*; 増田 明彦*; 原野 英樹*; 加藤 昌弘*; 島添 健次*
Journal of Instrumentation (Internet), 19(11), p.P11019_1 - P11019_16, 2024/11
被引用回数：0 パーセンタイル：0.00(Instruments & Instrumentation)A new LiCAF:Ce detector with an ultra-thick (99 
m) crystal and optimized readout was developed. The LiCAF:Ce and KG2 detectors were used to detect a sealed Cf-252 neutron source (neutron emission rate of ~
) using a 5 cm thick high-density polyethylene (HDPE) block located at the front of the detector. At the air kerma rates at the front surface of the HDPE block (
) of up to 1.07 Gy/h, the effective neutron count rate (
) for the LiCAF:Ce detector was the same within margins of errors, but it decreased by 5.7 
0.8% at 2.97 Gy/h. In contrast, for the KG2 detector, with increased up to 1.07 Gy/h, for KG2 increased up to 20 1.0 % at 1.07 Gy/h. Then, decreased by 20 1.0% at 2.97 Gy/h. Therefore, the LiCAF:Ce detector exhibited a smaller influence on neutron count rates by -rays compared to the KG2 detector because of the faster decay time and optimization of digital pulse processing.
Cf rotation method with a water Cherenkov neutron detector田辺 鴻典*; 米田 政夫; 藤 暢輔; 北村 康則*; 三澤 毅*; 土屋 兼一*; 相楽 洋*
Scientific Reports (Internet), 14, p.18828_1 - 18828_10, 2024/08
被引用回数：0 パーセンタイル：0.00(Multidisciplinary Sciences)The global challenge of on-site detection of highly enriched uranium (HEU), a substance with considerable potential for unauthorized use in nuclear security, is a critical concern. Traditional passive nondestructive assay (NDA) techniques, such as gamma-ray spectroscopy with high-purity germanium detectors, face significant challenges in detecting HEU when it is shielded by heavy metals. Addressing this critical security need, we introduce an on-site detection method for lead-shielded HEU employing a transportable NDA system that utilizes the Cf rotation method with a water Cherenkov neutron detector. This cost-effective NDA system is capable of detecting 4.17 g of 
U within a 12 min measurement period using a Cf source of 3.7 MBq. Integrating this system into border control measures can enhance the prevention of HEU proliferation significantly and offer robust deterrence against nuclear terrorism.
Kyffin, J.*; Dia, A.*; Nkosi, G.*; Nizhnik, V.*; 林 昭彦; 長谷 竹晃
Proceedings of 65th Annual Meeting of the Institute of Nuclear Materials Management (Internet), 8 Pages, 2024/07
In collaboration with the Japan Safeguards Office, the Nuclear Material Control Centre, and the JAEA, the IAEA Department of Safeguards is implementing a new neutron detector system for the verification of plutonium hold-up in process gloveboxes at MOX fuel fabrication facilities in Japan. The previous verification technique utilised the so-called Super Glove Box Assay System (SBAS), which, while capable of detecting partial defects, is a heavy and bulky detector system that requires both significant operator support for safe assembly and positioning, and long measurement times. The recent development of a detector system based on two Plutonium Neutron Coincidence Collar (PNCL) miniature neutron slabs provides the capability of detecting gross defects with semi-quantitative plutonium mass measurement, and is sufficient in respect to inspections for timeliness purposes. For regular use, the Mini-slab detector offers several advantages, including improved safety, reduced operator support requirements and shorter measurement times. The Mini-slab detector satisfies the required verification role with a quarter of the inspector-days compared to SBAS. Furthermore, it has the capability to measure in tighter spaces, with the need for such use expected to grow as parts of these facilities begin decommissioning.
Omer, M.; 静間 俊行*; 羽島 良一*; 小泉 光生
Journal of Applied Physics, 135(18), p.184903_1 - 184903_10, 2024/05
被引用回数：0 パーセンタイル：0.00(Physics, Applied)We report on the findings of a quantitative nondestructive analysis of the natural isotopic abundances of hafnium and tungsten elements using nuclear resonance fluorescence. Commercial samples of hafnium and tungsten were irradiated to six quasi-monochromatic -ray beams generated by laser Compton scattering in the energy range of 2.4-3.2 MeV. Multiple nuclei were simultaneously excited at each of the six -ray beam energies. A high-purity germanium detector array detected deexcitations of the nuclei. In total, 
transitions were unprecedentedly employed to estimate the isotopic abundances of heavy elements nondestructively. The estimated abundances of three hafnium isotopes and three tungsten isotopes are consistent with standard known natural abundances within the experimental uncertainties. The deviation from the standard values ranges from 0.18% to 1.36%. This work is a contribution of the Japan Atomic Energy Agency (JAEA) to the International Atomic Energy Agency (IAEA) under the agreement of the coordinated research program (CRP), J02015 (Facilitation of Safe and Secure Trade Using Nuclear Detection Technology - Detection of RN and Other Contraband). This work was a part of a study of the nuclear resonance fluorescence aiming at nuclear security and safeguards applications, being supported by the subsidiary for "promotion of strengthening nuclear security or the like" of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan.
Rodriguez, D.; Rossi, F.; 高橋 時音
IEEE Transactions on Nuclear Science, 71(3), p.255 - 268, 2024/03
被引用回数：0 パーセンタイル：0.00(Engineering, Electrical & Electronic)Under the MEXT subsidy to improve nuclear security related capabilities, we are developing the delayed gamma-ray spectroscopic analysis technique. One goal is to develop an inverse Monte Carlo analysis method using spectra from simulations of the interrogation instrument for comparison to the actual measured spectra. This work presents the validity of the Monte Carlo foundation of the analysis compared to experimental results and other simulation codes.
弘中 浩太; Lee, J.; 小泉 光生; 伊藤 史哲*; 堀 順一*; 寺田 和司*; 佐野 忠史*
Nuclear Instruments and Methods in Physics Research A, 1054, p.168467_1 - 168467_5, 2023/09
被引用回数：4 パーセンタイル：65.16(Instruments & Instrumentation)We propose neutron resonance fission neutron analysis (NRFNA), an active nondestructive assay (NDA) technique, to improve the capability to identify and quantify a small amount of fissile material in a sample. NRFNA uses pulsed neutrons to induce fission reactions in the sample. Fission neutrons are detected by a neutron-gamma pulse shape discrimination (PSD) scintillation detector with time-of-flight (TOF) technique. The obtained nuclide-specific resonance peaks in the neutron energy spectrum provide information to identify and quantify a fissile material in the sample. The possibility of using PSD for NRFNA was confirmed through a test experiment using a natural uranium sample. We successfully observed the resonance peaks from U(n,f) reaction and showed that NRFNA would be useful for measuring a small amount of fissile material in a sample.
Rossi, F.; 小泉 光生; Rodriguez, D.; 高橋 時音
Proceedings of INMM & ESARDA Joint Annual Meeting 2023 (Internet), 5 Pages, 2023/05
Since 2015, the Integrated Support Center for Nuclear Nonproliferation and Nuclear Security (ISCN) of the Japan Atomic Energy Agency has been working on the development of the Delayed Gamma-ray Spectroscopy non-destructive assay technique for the quantification of fissile-nuclide content in mixed nuclear materials. Thanks to the efforts and lessons learned from past experiments, the ISCN has successfully designed and fabricated a final integrated instrument. The instrument is composed of a moderator and dose shield where different neutron sources, like Cf-252 and neutron generators, can be inserted to irradiate the sample. Within the moderator, a series of neutron detectors are installed for perform prompt neutron analysis and continuous monitoring of the neutron source emission. Thanks to an innovative transfer system, the sample is then moved to the gamma-ray detector in less than 1.5s providing a fast and reliable movement while being safe from possible contamination. In this work, we will describe the design details of this new instrument. This work is supported by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) under the subsidy for the "promotion for strengthening nuclear security and the like".
Rodriguez, D.; Abbas, K.*; Bertolotti, D.*; Bonaldi, C.*; Fontana, C.*; 藤本 正己*; Geerts, W.*; 小泉 光生; Macias, M.*; Nonneman, S.*; et al.
Proceedings of INMM & ESARDA Joint Annual Meeting 2023 (Internet), 8 Pages, 2023/05
Under the MEXT subsidy to improve nuclear security related activities, we present the overview of the JAEA-JRC delayed gamma-ray spectroscopic analysis project. We describe past results, recent joint experiments, and the final goals for this project.
Rossi, F.; 小泉 光生; Rodriguez, D.; 高橋 時音
Proceedings of 2022 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room Temperature Semiconductor Detector Conference (2022 IEEE NSS MIC RTSD) (Internet), 2 Pages, 2022/11
To address challenges in the safeguard field for the verification of mixed nuclear materials, the Japan Atomic Energy Agency is developing the Delayed Gamma-ray Spectroscopy non-destructive assay technique. Minimally, this technique requires an external source to induce fission in the sample and a gamma-ray detector to collect the high-energy gamma rays emitted from the decay of fission products. In the development of this technique, deuterium-deuterium neutron generators will replace Cf as the external neutron source. The emitted neutrons are then slowed down in the thermal energy range to enhance the delayed gamma-ray signature coming from the fissile nuclides in the sample. The fission product delayed gamma rays with energy above 3 MeV are then collected with a detector located away from the irradiation position to avoid neutron damage. The collected spectrum is then analyzed, and the peak ratios are used to verify the initial composition of the fissile nuclides. Further, source monitors are required to normalize for the source emission to estimate the fissile mass of the sample. In this work, we will first describe our latest development in designing a delayed gamma-ray spectrometer for small mixed nuclear material samples. We will present latest results obtained from activation experiment and neutron detector characterization. Finally, we will present the usage of a new transfer system designed, fabricated, and tested at the Japan Atomic Energy Agency laboratories. This work is supported by MEXT under the subsidy for the "promotion for strengthening nuclear security and the like". This work was done under the agreement between JAEA and EURATOM in the field of nuclear material safeguards research and development.
Rossi, F.; 小泉 光生; Rodriguez, D.; 高橋 時音
Proceedings of INMM 63rd Annual Meeting (Internet), 5 Pages, 2022/07
With the initial goal of fissile-nuclide content quantification in small samples containing uranium and plutonium, the Integrated Support Center for Nuclear Nonproliferation and Nuclear Security of the Japan Atomic Energy Agency is developing the Delayed Gamma-ray Spectroscopy non-destructive assay technique. For this, while in the past years several experiments were conducted to prove the feasibility of the technique, a new instrument was designed considering the previous lessons learned. It includes a modular insertion for different neutron sources, like radioisotopes or neutron generators; a gamma-ray detector with improved data acquisition system allowing for real-time dead-time correction; and a full new mechanism for the sample transfer between irradiation and measurement. Together with this, neutron detectors are integrated to supplement the DGS mass analysis and monitor the source intensity. In this work, we will describe the new instrument and the preliminary results obtained from instrument characterization compared to previous experiments. This work is supported by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) under the subsidy for the "promotion for strengthening nuclear security and the like". This work was done under the agreement between JAEA and EURATOM in the field of nuclear material safeguards research and development.
Grazzi, F.*; Cialdai, C.*; Manetti, M.*; Massi, M.*; Morigi, M. P.*; Bettuzzi, M.*; Brancaccio, R.*; Albertin, F.*; 篠原 武尚; 甲斐 哲也; et al.
Rendiconti Lincei. Scienze Fisiche e Naturali, 32(3), p.463 - 477, 2021/09
被引用回数：6 パーセンタイル：29.95(Multidisciplinary Sciences)In this paper, we have studied an additively manufactured metallic component, intended for ultra-high vacuum application, the exit-snout of the MACHINA transportable proton accelerator beam-line. Metal additive manufacturing components can exhibit heterogeneous and anisotropic microstructures. Two non-destructive imaging techniques, X-ray computed tomography and Neutron Tomography, were employed to examine its microstructure. They unveiled the presence of porosity and channels, the size and composition of grains and intergranular precipitates, and the general behavior of the spatial distribution of the solidification lines. While X-ray computed tomography evidenced qualitative details about the surface roughness and internal defects, neutron tomography showed excellent ability in imaging the spatial density distribution within the component. The anisotropy of the density was attributed to the material building orientation during the 3D printing process. Density variations suggest the possibility of defect pathways, which could affect high vacuum performances. In addition, these results highlight the importance of considering building orientation in the design for additive manufacturing for UHV applications.
Rossi, F.; Abbas, K.*; 小泉 光生; Lee, H.-J.; Rodriguez, D.; 高橋 時音
Proceedings of INMM & ESARDA Joint Virtual Annual Meeting (Internet), 7 Pages, 2021/08
The Japan Atomic Energy Agency is developing the Delayed Gamma-ray Spectroscopy (DGS) non-destructive assay technique to quantify the fissile-nuclide content in small samples of mixed nuclear materials. One of our primary goals is to develop a compact and efficient DGS instrument to be easily installable into analytical laboratories. The instrument should include an external neutron source and a gamma-ray detection system along with other supporting systems like sample transfer and neutron monitoring. One of the challenges is to design a compact and efficient moderator for commercial neutron sources (e.g. neutron generators or sealed radioactive sources) that emit neutrons with high energy. However, to be able to enhance the gamma-ray signal from fissile materials, thermal neutrons are best due to their higher fission cross-sections. The choice of viable neutron source (neutron spectrum and strength) depends on several considerations (e.g. sample type and interrogation pattern), but also affect the gamma-ray measurement and the consequence analysis. In this work, we will first describe the evaluation results of our Delayed Gamma-ray Test Spectrometer using a Cf source (DGTS-C) from the first experiment carried out in PERLA in collaboration with the European Commission, Joint Research Centre. In association, we will describe how it provided guidance for our demonstration irradiator. Further, we will present our final moderator design concept for a deuterium-deuterium (D-D) neutron generator and present the latest results of data-model comparisons, including those with our PUNITA results. This work is supported by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) under the subsidy for the "promotion for strengthening nuclear security and the like". This work was done under the agreement between JAEA and EURATOM in the field of nuclear material safeguards research and development.
Rossi, F.; 小泉 光生; Lee, H.-J.; Rodriguez, D.; 高橋 時音; Abbas, K.*; Bogucarska, T.*; Crochemore, J.-M.*; Pedersen, B.*; Varasano, G.*
61st Annual Meeting of the Institute of Nuclear Materials Management (INMM 2020), Vol.2, p.907 - 911, 2021/00
Delayed Gamma-ray Spectroscopy (DGS) is a nondestructive assay technique with the capability to quantify the fissile composition of small nuclear material samples from reprocessing plants. In recent years, the Japan Atomic Energy Agency in collaboration with the Joint Research Centre performed several experiments using uranium and plutonium standard samples. In this paper, we present some of our recent experiment results showing the feasibility of DGS for fissile mass estimation. In particular, we interrogate uranium samples of different enrichment and we are showing that we were able to qualify significant peaks even for a depleted uranium sample above 2.7 MeV. Applying correction factors for neutron self-shielding and gamma self-absorption, we obtained a mass linear correlation when considering total integrated counts above 3.3 MeV as well as specific individual peak counts. This work is supported by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) under the subsidy for the "promotion for strengthening nuclear security and the like". This work was done under the agreement between JAEA and EURATOM in the field of nuclear material safeguards research and development.
涌井 隆; 若井 栄一; 直江 崇; 新宅 洋平*; Li, T.*; 村上 一也*; 鹿又 研一*; 粉川 広行; 羽賀 勝洋; 高田 弘; et al.
Journal of Nuclear Materials, 506, p.3 - 11, 2018/08
被引用回数：4 パーセンタイル：33.55(Materials Science, Multidisciplinary)J-PARCの核破砕中性子源の水銀ターゲット容器は、水銀容器と二重壁構造を持つ保護容器からなる薄肉(最小3mm)の多重容器構造で、TIG溶接により組み立てられる複雑な構造を持つ。容器の健全性を評価するためには、溶接部等の欠陥を正確に測定することが重要である。溶接部の非破壊検査方法として、放射線透過試験では検出が難しい欠陥形状等もあるので、超音波探傷試験の併用が有効である。JISで規定されている非破壊の超音波探傷試験方法では、厚さが6mm以上のものを対象としているため、薄肉構造の本容器の検査には適用できない。そこで、より有効な検査方法を開発するため、寸法が分かっている微小な欠陥を持つ試料に対して、様々な超音波探傷法による測定を試みた。その結果、最新のフェーズドアレイ法(FMC/TFM)では、計測値(約1.3mm)と実寸法(約1.2mm)とほぼ同じであり、これまで、欠陥測定が困難であった薄肉構造においても、正確な欠陥検知が可能であることが初めて分かった。
土屋 晴文; 北谷 文人; 藤 暢輔; Paradela, C.*; Heyse, J.*; Kopecky, S.*; Schillebeeckx, P.*
Proceedings of INMM 59th Annual Meeting (Internet), 6 Pages, 2018/07
In fields of nuclear safeguards and nuclear security, non-destructive assay (NDA) techniques are needed in order to quantify special nuclear materials (SNMs) in nuclear fuels. Among those techniques, active NDA ones would be preferable to passive ones. One candidate of active NDA techniques is neutron resonance transmission analysis (NRTA). In fact, experiments done at GELINA have shown that NRTA has high potential enough to quantify SNMs in complex materials. Currently, such a NRTA system requires a large electron accelerator facility to generate intense neutron sources. In other words, it is very difficult to perform NRTA at various facilities that need to measure SNMs. Thus, downsizing a NRTA system would be one solution of its difficulty. In order to realize a compact NRTA system, we develop a prototype with a D-T neutron generator that has a pulse width of 10 s. For this aim, numerical calculations to optimize the compact NRTA system were done. In addition, NRTA measurements with simulated fuel pins were made at neutron time-of-flight facilities such as GELINA. In this presentation, we present results of the numerical calculations and the experimental results. On the basis of those results we discuss a future prospect of a compact NRTA system that would be applicable to SNM quantification. This research was implemented under the subsidiary for nuclear security promotion of MEXT.
Rodriguez, D.; Rossi, F.; 高橋 時音; 瀬谷 道夫; 小泉 光生; Crochemore, J. M.*; Varasano, G.*; Bogucarska, T.*; Abbas, K.*; Pedersen, B.*
Proceedings of INMM 59th Annual Meeting (Internet), 7 Pages, 2018/07
DGS has great potential for HRNM, since it determines fissile nuclide compositions by correlating the observed DG spectrum to the unique FY of the individual nuclides. Experiments were performed with LRNM using both PUNITA and a JAEA designed Cf-shuffler tested in PERLA. The data was analyzed using an inverse MC method that both determines DG peak intensity correlations and provides an evaluation of the uncertainty of the measurements. The results were used to verify DG signatures for varying fissile compositions, total fissile content, and DGS interrogation timing patterns. Future development will focus on measuring HRNM and designing a compact system by evaluating different neutron sources, moderating materials, and detection capabilities. This presentation summarizes the JAEA/JRC DGS program to date and the future direction of this collaborative work performed using the MEXT subsidy for the promotion of strengthening nuclear security.
古澤 彰憲; 西村 昭彦; 武部 俊彦*; 中村 将輝*; 竹仲 佑介*; 西條 慎吾*; 中本 裕之*
E-Journal of Advanced Maintenance (Internet), 9(2), p.44 - 51, 2017/08
本論文では、配管のレーザー突合せ溶接に対して超音波ガイド波検査法が適用可能であるかを調査する。10種類の異なる溶接条件で作成した突合せ溶接配管試験体に対して超音波ガイド波試験を行い、検査信号の解析を行った。励起した超音波ガイド波はTモードガイド波であって、その励起と受信にはEMATを使用した。試験で得られたガイド波信号を解析することで溶接不良部からのガイド波検出信号が明瞭に測定される一方、十分に溶け込んだ溶接部からは反射信号がなく、突合せ溶接された溶接部の状況とガイド波検出信号に相関があることを確認し、超音波ガイド波検査法はレーザー突合せ溶接に対して適用可能性があることを示した。
細馬 隆
JAEA-Research 2016-019, 53 Pages, 2017/01
JAEA-Research-2016-019.pdf:5.71MB
核物質非破壊測定システムの基礎への確率母関数の適用について研究を行った。最初に、高次の中性子相関を七重相関まで代数的に導出し、その基本的な性格を調べた。高次の中性子相関は、漏れ増倍率の増大に応じて急速に増大し、検出器の効率や設定によるが漏れ増倍率が1.3を超えると、より低次の中性子相関と交わり追い越してゆくことを見出した。続いて、高速中性子と熱中性子が共存する系において、高速中性子による核分裂数と二重相関計数率及び熱中性子による核分裂数と二重相関計数率を、代数的に導出した。従来の測定法と、differential die-away self-interrogation法によって得られるRossi-alpha結合分布と各エリアの面積比を用いれば、高速中性子と熱中性子それぞれの単位時間あたりの誘導核分裂数、ソース中性子1個あたりそれぞれの誘導核分裂数(1未満)及びそれぞれの二重相関計数率を、推定可能であることを見出した。
直井 洋介; 小田 哲三; 富川 裕文
日本原子力学会誌ATOMO
, 58(9), p.536 - 541, 2016/09
日本は1955年に制定された原子力基本法に従い、原子力の研究開発、原子力エネルギーの利用を平和目的に限って推進してきた。平和目的に限られていることを担保するため、事業者は計量管理を行い、IAEAと保障措置協定を締結する以前は二国間原子力協定(日米,日仏,日加等)に基づき報告を行い、1977年のIAEAとの保障措置協定を締結後は国内法が改定され、それに基づき計量管理及びその報告が行われてきた。1999年には追加議定書を締結して新たな義務を負うIAEAの保障措置活動に対応してきており、これまでわが国の原子力活動についての申告の正確性と完全性がIAEAによって検認されてきている。2004年には、核物質の転用や未申告の活動はないとの「拡大結論」を得て以降、これまで毎年この拡大結論を得てきている。本報告では、原子力機構がこれまで取り組んできたIAEAの保障措置に必要な技術開発や人材育成への協力などIAEA保障措置活動への貢献について報告する。
荻原 徳男; 引地 裕輔; 神谷 潤一郎; 金正 倫計
Journal of the Vacuum Society of Japan, 59(4), p.79 - 82, 2016/04
In order to demonstrate the function of the gas sheet for measuring the 2 dimensional profiles of the accelerated beams, the following experiments were carried out: (1) The gas sheet with a thickness of 1.5 mm and the density of 2
10
Pa was generated by the combination of the deep slit and the thin slit. Here, the gas sheet was produced by the deep slit, and the shape of the sheet was improved by the thin slit. (2) For the electron beam of 30 keV with a diameter greater than 0.35 mm, the position and the two-dimensional profiles were well measured using the gas sheet.
