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Rodriguez, D.; 赤松 駿介*; Rossi, F.; 鈴木 敏*; 高橋 時音
Proceedings of 65th Annual Meeting of the Institute of Nuclear Materials Management (Internet), 9 Pages, 2024/07
Under the MEXT subsidy to promote nuclear security related activities, we will present the preliminary results from the new Fission Signature Assay Instrument that was fabricated and fully installed in November 2023. We will describe the instrument within the context of the JAEA-JRC collaboration development and the experimental activities planned with it in the larger context of finishing off Phase-III development.
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.
Rodriguez, D.; 赤松 駿介*; Rossi, F.; 鈴木 敏*; 高橋 時音
第44回日本核物質管理学会年次大会会議論文集(インターネット), 4 Pages, 2023/11
Under the MEXT subsidy for improving nuclear material security related activities, we present the latest JAEA/ISCN delayed gamma-ray instrument, FSAI; preliminary characterization results; and the experimental and analysis development activities planned using it.
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.
Rodriguez, D.; Rossi, F.
Proceedings of INMM & ESARDA Joint Annual Meeting 2023 (Internet), 9 Pages, 2023/05
Under the MEXT subsidy for the improvement of nuclear security related activities, we will present on the current and future progress of the delayed gamma-ray spectroscopic analysis development. We highlight a paper soon to be released and the plan for finalizing the project goal.
Rodriguez, D.; 小泉 光生; Rossi, F.; 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), 3 Pages, 2022/12
Under the MEXT subsidy to improve nuclear security related activity, we present our latest analytical development of delayed gamma spectroscopic (DGS) analysis for nuclear safeguards. We show the latest results from the ISCN DGS Monte Carlo and comparisons with measured spectra. We highlight differences with other simulation codes, which highlights discrepancies in fission yields from nuclear data and our future direction to improve this for optimal safeguards measurements and reduced uncertainty. We will also summarize how the analysis will be applied with a new instrument designed for small samples for validation of the DGS technique, as well as how this can be applied to full assemblies and alternative fuel cycles.
Rodriguez, D.; 小泉 光生; Rossi, F.; 高橋 時音
第43回日本核物質管理学会年次大会会議論文集(インターネット), 4 Pages, 2022/11
Under the MEXT subsidy to promote the development of nuclear security related activities, we present our latest delayed gamma-ray spectroscopy analysis and instrument developments. We will highlight important past results, current activities, and future plans.
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.
Rodriguez, D.; 小泉 光生; Rossi, F.; 高橋 時音; Abbas, K.*; Nonneman, S.*; Pedersen, B.*; Oberstedt, S.*; Schillebeeckx, P.*
Proceedings of International Safeguards; Reflecting on the Past and Anticipating the Future, 7 Pages, 2022/10
Under the MEXT subsidy to develop nuclear security, the ISCN is investigating the Delayed Gamma-ray Spectroscopic analysis technique to evaluate mixed nuclear materials. Primarily we are focusing on developing the analysis for any form of mixed nuclear material, but dominantly used nuclear fuel that is challenging due to the long-lived fission products and minor actinides hiding the U and Pu signatures. We describe the analysis we are developing and the associated instrumentation to interrogate the sample. We show that this can be applied to small samples and assemblies, as well as alternative fuel cycle materials.
Rodriguez, D.; Abbas, K.*; 小泉 光生; Nonneman, S.*; Oberstedt, S.*; Pedersen, B.*; Rossi, F.; Schillebeeckx, P.*; 高橋 時音
Proceedings of INMM 63rd Annual Meeting (Internet), 9 Pages, 2022/09
Under the MEXT subsidy to develop nuclear security related technology, we present the overview and ISCN analysis development of the Delayed Gamma-ray Spectroscopic Analysis project. We summarize the past analysis and instrumentation results and highlight how this affects the evaluation of fissile nuclides in spent nuclear fuel. We further discuss the direction of the third development phase.
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.
Rodriguez, D.; Abbas, K.*; 小泉 光生; Nonneman, S.*; Rossi, F.; 高橋 時音
Nuclear Instruments and Methods in Physics Research A, 1014, p.165685_1 - 165685_10, 2021/10
被引用回数：4 パーセンタイル：43.33(Instruments & Instrumentation)Under the MEXT subsidy on research for improving nuclear security related development, we designed the Delayed Gamma-ray Californium Test (DGCT) instrument. From He-3 count-rate experiments performed in collaboration with the European Commission Joint Research Centre, we show the effective neutron flux entering the sample space. Further, we show delayed gamma-ray spectra of both U and Pu samples as well as a comparison to the background from Cf activation of the environment. Finally, we make comparisons to earlier spectra obtained using PUNITA, including relative fission capability, spectral signature, and mass correlations.
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.
Rodriguez, D.; Bogucarska, T.*; 小泉 光生; Lee, H.-J.; Pedersen, B.*; Rossi, F.; 高橋 時音; Varasano, G.*
Nuclear Instruments and Methods in Physics Research A, 997, p.165146_1 - 165146_13, 2021/05
被引用回数：2 パーセンタイル：24.88(Instruments & Instrumentation)Under the MEXT subsidy to strengthen nuclear security related research, the ISCN is developing delayed gamma-ray spectroscopy (DGS) for nuclear safeguards. Here we present results from experiments using the PUNITA instrument in collaboration with JRC-Ispra to evaluate the gamma-ray spectral dependence on interrogation time patterns and number of cycles. Specifically, we investigated the observable gamma rays useful to quantify the 
Pu and 
U contributions. Of the time patterns tested in this study, we determined that irradiating the sample for 60-
followed by a gamma-ray measurement of 60- was the best for a comparable one-hour total interrogation time.
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.
Rodriguez, D.; 小泉 光生; Rossi, F.; 瀬谷 道夫; 高橋 時音; Bogucarska, T.*; Crochemore, J.-M.*; Pedersen, B.*; 高峰 潤
Journal of Nuclear Science and Technology, 57(8), p.975 - 988, 2020/08
被引用回数：4 パーセンタイル：34.76(Nuclear Science & Technology)Present safeguards verification methods of high-radioactivity nuclear material use destructive analysis techniques since passive nondestructive techniques are incapable of determining the nuclear material content. To improve this verification process, the JAEA and EC-JRC Ispra, Italy have been collaborating to develop delayed gamma-ray spectroscopy for composition analysis of the fissile nuclides as an aspect of the MEXT subsidy for improving nuclear security and the like. Multiple experiments were performed over three years using PUNITA to interrogate U and Pu samples to determine the signature from the short-lived fission products. We observed many gamma rays useful to determine the composition of a mixed nuclear material sample. Presented here are the results of these measurements with correlations to the interrogation, mass, volume, and sample homogeneity.
Cf for safeguards verification measurementsRodriguez, D.; Rossi, F.; 高橋 時音; 瀬谷 道夫; 小泉 光生
Applied Radiation and Isotopes, 148, p.114 - 125, 2019/06
被引用回数：6 パーセンタイル：47.17(Chemistry, Inorganic & Nuclear)Delayed gamma-ray spectroscopy is an active-NDA technique used to determine the composition of HRNM samples by peak-ratio comparison of GRs above 3-MeV from the short-lived fission products. Filtering out the passive GRs from long-lived FPs reduces the DGS signal, so thermal neutrons are used to induce more fission events from fissile nuclides. We are developing a compact system to moderate 
2-MeV neutrons that are easier to moderate than 14-MeV neutrons from DT generators. This work describes the ideal moderator optimization for a Cf source that results in 
cm
passing through the sample space with 
70% of those below 1-eV. Practical modifications resulted in 
20% reductions compared to the optimized design. Evaluations of DGS signals and backgrounds conclude that only a 21-MBq Cf source is required.
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.
Rodriguez, D.; Rossi, F.; 高峰 潤; 小泉 光生; 瀬谷 道夫; Crochemore, J. M.*; Varasano, G.*; Bogucarska, T.*; Abbas, K.*; Pedersen, B.*
Proceedings of INMM 58th Annual Meeting (Internet), 6 Pages, 2017/07
原子力機構は、4つのアクティブ法を組合せたNDAシステムの開発をEC-JRCと共同で実施している。遅発
線分光法は核分裂性核種の組成比を決定することができるもので、観測する核分裂生成核種の時間依存型の、高エネルギー線を、サンプルの複雑な核分裂収率と関連付けて分析するものである。興味のある核分裂性核種比を定量するためには、使用する(小型の持ち運びが可能な)中性子源からの速中性子を、核分裂反応断面積の大きな熱中性子までエネルギーを下げつつ、有意な計数信号を得るためのフラックス強度を必要とする。現在、遅発線分光法の改良のため、JRC-IspraのPUNITAを含むいくつかの施設での実験が進行中である。これらの中性子フラックス、測定環境等データは、遅発線分光データの分析を行うモンテカルロ法(逆モンテカルロ法)の開発に使われる。ここでの遅発線分光法は、その実証に関して、これまでの開発成果である減速系の最適化、実験、逆モンテカルロ法についてまとめる。
Rossi, F.; Abbas, K.*; 小泉 光生; Lee, H.-J.; Nonneman, S.*; Pedersen, B.*; Rodriguez, D.; 高橋 時音
no journal, ,
In the field of nuclear material samples safeguard verifications, mixed high-radioactivity nuclear material in facility like reprocessing nuclear plant are challenging. Addressing this, the JAEA/ISCN is developing a DG-nondestructive assay technique. We successfully completed several experiments in collaboration with the EC/JRC to evaluate the instrumentation requirements of a compact instrument. In principle, a neutron source is used to produce neutrons that are then thermalized in a moderator before reaching the sample to induce fission. The optimization of the moderator is crucial to reach an efficient and compact instrument. Having a good thermalized neutron flux enhances the delayed gamma-ray signature of the fissile due to their greater thermal fission cross section compared to the fertile. After the irradiation, the gamma-ray peaks above 3 MeV are analyzed to determine the initial composition of the fissile nuclides. The gamma-ray spectrum and subsequent analysis are strongly affected by the source type; the sample; and the interrogation pattern, driven by the analysis. To investigate all these aspects, we performed several experiments using small standard samples of both Uranium and Plutonium with PUNITA to understand basic principles. These were factored into the JAEA DGCT instrument that was tested in PERLA. This work first describes the PUNITA and PERLA experiments and how these were used to validate the various model designs. From these, further modifications to reach our final instrument concept design for a deuterium-deuterium neutron generator source are presented. 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.
