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Performance of large volume LaBr$$_{3}$$ scintillation detector equipped with specially-designed shield for neutron resonance capture analysis

土屋 晴文; 小泉 光生; 北谷 文人; 原田 秀郎

Nuclear Instruments and Methods in Physics Research A, 932, p.16 - 26, 2019/07

A large-volume ($$phi$$12.0 cm$$times$$12.7 cm) LaBr$$_{3}$$ scintillation detector equipped with a specially-designed radiation shield was evaluated for neutron resonance capture analysis at the neutron time-of-flight (TOF) facility GELINA. By using the LaBr$$_{3}$$ detector with and without the shield, measurements were carried out at a 13-m TOF station with three metallic samples, namely, Ni, Cr, and Fe. In addition, Monte Carlo simulations with Geant4 were performed, and the results were compared with the measurements to analyze the observed energy spectra and TOF spectra. Energy spectra obtained with the shield showed that prompt $$gamma$$-ray peaks emitted from each sample can be used to identify the isotopes. Moreover, the signal-to-noise ratios of resonance peaks in a TOF spectrum with the shield were enhanced 1.5-2.5 in comparison with those without the shield. Furthermore, simultaneous measurements conducted using the three samples demonstrated that the shield employed herein was indispensable for identifying impurities in a composite sample such as particle-like fuel debris.


Development of differential die-away technique in an integrated active neutron NDA system for nuclear non-proliferation and nuclear security

大図 章; 前田 亮; 米田 政夫; 藤 暢輔; 小泉 光生; 瀬谷 道夫

Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 4 Pages, 2018/11

A Differential Die-away Analysis (DDA) system using a compact pulsed neutron (14 MeV) generator has been newly developed for non-nuclear proliferation and nuclear security in the Japan Atomic Energy Agency (JAEA). The DDA system was designed to be able to detect a nuclear fissile material (Pu-239) of as low as 10 mg and to handle samples of a different volume: a vial bottle (20 mL), a pail container (20 L), through a Monte Carlo simulation. In the DDA system, the Fast Neutron Direct Interrogation (FNDI) technique, which utilizes fast neutrons for interrogation, was applied to measure the amount of fissile mass contained in the sample. The fundamental performance of the DDA system was investigated in the demonstration experiment. The simulation results show that the Pu-239 masses of less than 10 mg can be detected in the DDA system. The results of the experiment are discussed and compared with those of the simulation.


Dynamic nuclear self-polarization of III-V semiconductors

小泉 光生; 後藤 淳*; 松木 征史*

Journal of Semiconductors, 39(8), p.082001_1 - 082001_5, 2018/08

動的自己核偏極(Dynamic nuclear self-polarization, DYNASP)はIII-V族半導体で見られる現象で、価電子帯の電子をレーザーで伝導帯に励起すると、数K程度の臨界温度以下で大きな核偏極が得られる。我々は、Dyakonovらの理論を拡張し、円偏光したレーザーによって励起した電子のスピン分布を偏らせた場合や、外部磁場がある場合の核偏極現象への影響を調べた。その結果、励起された電子スピン分布の偏りにより、臨界温度近くにおいても核偏極が得られることを明らかにした。また、外部磁場も電子スピン分布偏極と同じような影響を及ぼすことを明らかにした。こうした現象を実験的に調べるため、低温での実験ができる装置を開発し、実験の準備を進めているので、その報告もあわせて行う。


Demonstration of $$gamma$$-ray pipe-monitoring capabilities for real-time process monitoring safeguards applications in reprocessing facilities

Rodriguez, D.; 谷川 聖史; 西村 和明; 向 泰宣; 中村 仁宣; 栗田 勉; 高峰 潤; 鈴木 敏*; 関根 恵; Rossi, F.; et al.

Journal of Nuclear Science and Technology, 55(7), p.792 - 804, 2018/07

 パーセンタイル:100(Nuclear Science & Technology)



Development of active neutron NDA system for nuclear materials

藤 暢輔; 大図 章; 土屋 晴文; 古高 和禎; 北谷 文人; 米田 政夫; 前田 亮; 小泉 光生; Heyse, J.*; Paradela, C.*; et al.

Proceedings of INMM 59th Annual Meeting (Internet), 9 Pages, 2018/07

Nuclear material accountancy is of fundamental importance for nuclear safeguards and security. However, to the best of our knowledge, there is no established technique that enables us to accurately determine the amount of Special Nuclear Materials (SNM) and Minor Actinides (MA) in high radioactive nuclear materials. Japan Atomic Energy Agency (JAEA) and the Joint Research Centre (JRC) of the European Commission Collaboration Action Sheet-7 started in 2015. The purpose of this project is to develop an innovative non-destructive analysis (NDA) system using a D-T pulsed neutron source. Active neutron NDA techniques, namely Differential Die-Away Analysis (DDA), Prompt Gamma-ray Analysis (PGA), Neutron Resonance Capture Analysis (NRCA), Neutron Resonance Transmission Analysis (NRTA) and Delayed Gamma-ray Analysis (DGA) have been studied and developed. The different methods can provide complementary information which is particularly useful for quantification of SNM and MA in high radioactive nuclear materials. The second phase of the project has started. In the second phase, we will continue to conduct additional research to improve the methodology and develop an integrated NDA system. This presentation gives an overview of the project and the NDA system and reports the recent results. This research was implemented under the subsidiary for nuclear security promotion of MEXT.


Development of detection and measurement technologies for Nuclear Non-proliferation and Security at JAEA

小泉 光生; 瀬谷 道夫; 富川 裕文; 堀 雅人; 直井 洋介

Proceedings of INMM 59th Annual Meeting (Internet), 8 Pages, 2018/07



Delayed $$gamma$$-ray spectroscopy combined with active neutron interrogation for nuclear security and safeguards

小泉 光生; Rossi, F.; Rodriguez, D.; 高峰 潤; 瀬谷 道夫; Bogucarska, T.*; Crochemore, J.-M.*; Varasano, G.*; Abbas, K.*; Pedersen, B.*; et al.

EPJ Web of Conferences (Internet), 146, p.09018_1 - 09018_4, 2017/09


Along with the global increase of applications using nuclear materials (NM), the requirements to nuclear security and safeguards for the development of effective characterization methods are growing. Mass verification of NM of low radioactivity is performed using passive non-destructive analysis (NDA) techniques whereas destructive analysis (DA) techniques are applied for accurate analysis of nuclide composition. In addition to the characterization by passive NDA, a sample can be further characterized by active NDA techniques. An active neutron NDA system equipped with a pulsed neutron generator is currently under development for studies of NDA methods. Among the methods DGS uses the detection of decay $$gamma$$-rays from fission products (FP) to determine ratios of fissile nuclides present in the sample. A proper evaluation of such $$gamma$$-ray spectra requires integration of nuclear data such as fission cross-sections, fission yields, half-lives, decay chain patterns, and decay $$gamma$$-ray emission probabilities. The development of the DGS technique includes experimental verification of some nuclear data of fissile materials, as well as development of the device. This presentation will be a brief introduction of the active neutron NDA project and an explanation of the DGS development program.


Neutron resonance analysis for nuclear safeguards and security applications

Paradela, C.*; Heyse, J.*; Kopecky, S.*; Schillebeeckx, P.*; 原田 秀郎; 北谷 文人; 小泉 光生; 土屋 晴文

EPJ Web of Conferences (Internet), 146, p.09002_1 - 09002_4, 2017/09


Neutron-induced reactions can be used to study the properties of nuclear materials in the field of nuclear safeguards and security. The elemental and isotopic composition of these materials can be determined by using the presence of resonance structures in the reaction cross sections as fingerprints. This idea is the basis of two non-destructive analytical techniques which have been developed at the GELINA neutron time-of-flight facility of the JRC-IRMM: Neutron Resonance Capture Analysis (NRCA) and Neutron Resonance Transmission Analysis (NRTA). A full quantitative validation of the NRTA technique was obtained by determining the areal densities of enriched reference samples used for safeguards applications with an accuracy better than 1%. Moreover, a combination of NRTA and NRCA has been proposed for the characterisation of particle-like debris of melted fuel formed in severe nuclear accidents. In order to deal with the problems due to the diversity in shape and size of these samples and the presence of strong absorbing matrix materials, new capabilities have been implemented in the resonance shape analysis code REFIT. They have been validated by performing a blind test in which the elemental abundance of a combined sample composed of unknown quantities of materials such as cobalt, tungsten, rhodium or gold was determined with accuracies better than 2%.


Influence of the neutron transport tube on neutron resonance densitometry

北谷 文人; 土屋 晴文; 小泉 光生; 高峰 潤; 堀 順一*; 佐野 忠史*

EPJ Web of Conferences (Internet), 146, p.09032_1 - 09032_3, 2017/09


The use of a short flight path is effective in the neutron resonance analysis. On the other hand, such a short path would reduce a time resolution in Time-Of-Flight (TOF) measurements. In order to investigate the effect of neutron flight-path length, we carried out Neutron Resonance Transmission Analysis (NRTA) experiments with a short neutron flight path at the Kyoto University Research Reactor Institute - Linear Accelerator (KURRI-LINAC). In measurements of Neutron Resonance Densitometry, the quantity of nuclear materials is determined from TOF spectra obtained in the neutron energy range below 30 eV. Performing NRTA experiments with a 7-m flight path at KURRI-LINAC, we examined effects of flight path and pulse width on a TOF spectrum. A resonance dip of $$^{183}$$W at 27 eV in a TOF spectrum was successfully observed with an electron pulse width less than 2 $$mu$$s. In this presentation, we will discuss importance of the pulse width and short flight path to study design of a compact TOF facility to quantify nuclear materials.


Intermediate-spin states of $$^{92}$$Zr and a large $$B(E2)$$ value between the $$10_1^+$$ and $$8_1^+$$ states

菅原 昌彦*; 藤 暢輔; 小泉 光生; 大島 真澄*; 木村 敦; 金 政浩*; 初川 雄一*; 草刈 英榮*

Physical Review C, 96(2), p.024314_1 - 024314_7, 2017/08

 パーセンタイル:100(Physics, Nuclear)

This study investigated intermediate spin states of $$^{92}$$Zr via the inverse reaction $$^9$$Be($$^{86}$$Kr,3n)$$^{92}$$Zr. Seven transitions were newly observed and a lifetime was extracted for the $$10_1^+$$ state by analysis of Doppler-broadened line shapes of decay $$gamma$$-rays. A large $$B(E2)$$ value was obtained for the transition from $$10_1^+$$ to $$8_1^+$$ and the magnitude was comparable to that for the deformed excited configurations in $$^{94}$$Zr that have recently been established. A possible origin for such collectivity is discussed qualitatively based on a phenomenological deformed rotor model. Moreover, a multiplet-like structure that fits into the systematics for $$N=52$$ even-A isotones is revealed for the negative-parity yrast states.


Delayed gamma-ray spectroscopy, 1; Development and current status

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



Delayed gamma-ray spectroscopy, 2; Experimental studies for determination of fissile materials ratios

Rossi, F.; 小泉 光生; Rodriguez, D.; 高峰 潤; 瀬谷 道夫; Pedersen, B.*; Crochemore, J. M.*; Abbas, K.*; Bogucarska, T.*; Varasano, G.*

Proceedings of INMM 58th Annual Meeting (Internet), 7 Pages, 2017/07

保障措置分野では、高線量核物質の核分裂性核種の組成比の独立検認のために、新たな、改良アクティブ問い掛け法NDA技術が必要とされている。原子力機構とJoint Research Centre (JRC)は、サンプルの核分裂生成核種の崩壊からの遅発$$gamma$$線を測定することで、サンプル中核物質の核分裂性核種比を決める遅発$$gamma$$線分光法を共同で開発している。現在、低線量核物質サンプルを用いた測定がいくつかの施設で行われることとなっている。ここで、長半減期核分裂生成核種からの影響を最小限にするために、低エネルギー$$gamma$$線の遮へいと、3MeVを超える高いエネルギーの$$gamma$$線に注目する必要がある。この測定法では、異なる小型中性子源が使用されるが、いずれにおいても中性子エネルギーを熱エネルギー領域まで減速することが必要である。我々は、減速体及び反射体をMCNPを用いて最適化を進めており、また、問い掛け、移動、測定のシークエンスの最適化も進めている。現在進めている測定では、認証されたU/Puサンプルを使用しており、観測する遅発$$gamma$$線を同位体組成に比例する関連付けが可能となる。この発表では、最適化の状況とともに、U/Puサンプル中の核分裂性核種比決定のための実験キャンペーンを紹介する。


$$gamma$$-ray pipe monitoring for comprehensive safeguards process monitoring of reprocessing facilities

Rodriguez, D.; 谷川 聖史; 向 泰宣; 磯前 日出海; 中村 仁宣; Rossi, F.; 小泉 光生; 瀬谷 道夫

Proceedings of INMM 58th Annual Meeting (Internet), 9 Pages, 2017/07



Effects of $$gamma$$-ray polarization in NRF-based nondestructive assay of nuclear materials

Omer, M.; 羽島 良一*; 静間 俊行*; 小泉 光生

Proceedings of INMM 58th Annual Meeting (Internet), 7 Pages, 2017/07



Development of active neutron NDA techniques for nuclear nonproliferation and nuclear security

藤 暢輔; 大図 章; 土屋 晴文; 古高 和禎; 北谷 文人; 米田 政夫; 前田 亮; 呉田 昌俊; 小泉 光生; 瀬谷 道夫; et al.

EUR-28795-EN (Internet), p.684 - 693, 2017/00

In 2015, Japan Atomic Energy Agency (JAEA) and the Joint Research Centre (JRC) of the European Commission collaboration started to develop an active neutron non-destructive assay system for nuclear nonproliferation and nuclear security. To the best of our knowledge, no adequate technique exists that allows us to determine the amount of special nuclear materials and minor actinides in high radioactive nuclear materials, such as spent fuel, transuranic waste, etc. The collaboration aims at contributing to the establishment of an innovative NDA system using a D-T pulsed neutron source for various applications. We utilize several active neutron NDA techniques, namely Differential Die-Away Analysis (DDA), Prompt Gamma-ray Analysis (PGA), Neutron Resonance Capture Analysis (NRCA), Neutron Resonance Transmission Analysis (NRTA) and Delayed Gamma Spectroscopy (DGS). All of these techniques have advantages and disadvantages. The different methods can provide complementary information which is particularly useful for nuclear nonproliferation and nuclear security. In this project, we have developed a combined NDA system, which enables the measurements of DDA and PGA, at NUclear fuel Cycle safety Engineering research Facility (NUCEF) in JAEA. In this presentation, we will introduce our project and report the recent progress of developments, especially in NRTA, DDA and PGA.


Delayed gamma-ray analysis for characterization of fissile nuclear materials

小泉 光生; Rossi, F.; Rodriguez, D.; 高峰 潤; 瀬谷 道夫; Bogucarska, T.*; Crochemore, J.-M.*; Varasano, G.*; Abbas, K.*; Pedersen, B.*; et al.

EUR-28795-EN (Internet), p.868 - 872, 2017/00

Under the collaboration between the Japan Atomic Energy Agency (JAEA) and European Commissions' Joint Research Center (EC-JRC), development of four active neutron-interrogation non-destructive assay methods for nuclear non-proliferation and safeguards are in progress. The techniques are differential die-away analysis, delayed gamma-ray analysis (DGA), neutron resonance transmission analysis, and prompt gamma-ray analysis. Information obtained by each method is used complementarily to characterize a sample. DGA utilizes moderated pulsed neutrons from a D-T neutron generator to induce fission reaction of nuclear materials. Delayed gamma rays from the fission products (FP) are measured to determine the ratios of fissile nuclides (e.g. $$^{235}$$U, and $$^{239,241}$$Pu) in the sample. Experimental studies of the DGA method are in progress with the Pulsed Neutron Interrogation Test Assembly (PUNITA) in EC-JRC Ispra. Here we present an overview of the study plan of these DGA experiments along with the latest results. This research was implemented under the subsidiary for nuclear security promotion of MEXT.


$$^3$$He代替非破壊分析装置の開発; 迫り来る$$^3$$Heクライシスの解決を目指して

小泉 光生; 坂佐井 馨; 呉田 昌俊; 中村 仁宣

日本原子力学会誌, 58(11), p.642 - 646, 2016/11

核セキュリティ、保障措置分野では、核分裂に伴う中性子を検出する検認装置として$$^3$$He検出器を利用したものが広く利用されている。検出器に利用される$$^3$$Heガスは、主に米国におけるストックから供給されてきたが、2001年9月11日の同時多発テロ以後、大量の$$^3$$He中性子検知装置を米国内に配備したことから、在庫が減少し、供給が近い将来停止する状況になりつつあった。そうした中、2011年3月末の$$^3$$He代替中性子検出技術に関するワークショップにおけるIAEAの$$^3$$He代替非破壊分析装置開発の呼びかけに応じ、原子力機構においても、J-PARCセンターが開発したZnS/$$^{10}$$B$$_2$$O$$_3$$セラミックシンチレータをベースに$$^3$$He代替検出器の開発を行い、平成27年3月には、開発した中性子検出装器の性能試験及びそれを実装した核物質検認用非破壊分析(Non-Destructive Assay (NDA))装置の性能実証試験を実施した。本解説では、開発した検出器、代替NDA装置を紹介し、あわせて$$^3$$He問題の顛末を報告する。


LaBr$$_3$$ $$gamma$$-ray spectrometer for detecting $$^{10}$$B in debris of melted nuclear fuel

小泉 光生; 土屋 晴文; 北谷 文人; 原田 秀郎; Heyse, J.*; Kopecky, S.*; Mondelaers, W.*; Paradela, C.*; Schillebeeckx, P.*

Nuclear Instruments and Methods in Physics Research A, 837, p.153 - 160, 2016/11

 被引用回数:1 パーセンタイル:76.09(Instruments & Instrumentation)

Neutron Resonance Densitometry (NRD) has been proposed as a non-destructive analytical method for quantifying Special Nuclear Material (SNM) in the rock- and particle-like debris that is to be removed from the Fukushima Daiichi Nuclear Power Plant. The method is based on Neutron Resonance Transmission Analysis (NRTA) and Neutron Resonance Capture Analysis combined with Prompt Gamma Ray Analysis (NRCA/PGA). Although quantification of SNM will predominantly rely on NRTA, this will be hampered by the presence of strong neutron-absorbing matrix materials, in particular $$^{10}$$B. Results obtained with NRCA/PGA are used to improve the interpretation of NRTA data. Prompt $$gamma$$-rays originating from the $$^{10}$$B(n, $$alphagamma$$) reaction are used to assess the amount of $$^{10}$$B. The 478 keV $$gamma$$-rays from $$^{10}$$B, however, need to be measured under a high-radiation environment, especially from $$^{137}$$Cs. In order to meet this requirement, we have developed a well-shaped $$gamma$$-ray spectrometer consisting of a cylindrical and four rectangular cuboid LaBr$$_3$$ scintillators, and a fast data acquisition system.


複雑な組成・形状の核燃料を計量管理する中性子共鳴濃度分析法の開発; 粒子状溶融燃料中の核物質非破壊測定技術の開発

小泉 光生; 原田 秀郎; Schillebeeckx, P.*

日本原子力学会誌, 58(9), p.563 - 567, 2016/09



Development of active neutron NDA techniques for nuclear nonproliferation and nuclear security, 7; Measurement of DG from MOX and Pu liquid samples for quantification and monitoring

向 泰宣; 小川 剛; 中村 仁宣; 栗田 勉; 関根 恵; Rodriguez, D.; 高峰 潤; 小泉 光生; 瀬谷 道夫

Proceedings of INMM 57th Annual Meeting (Internet), 7 Pages, 2016/07

核不拡散用のアクティブ中性子非破壊測定技術開発の一環として、核分裂性核種($$^{239}$$Pu, $$^{241}$$Pu, $$^{235}$$U)の組成比を分析するために、3MeV超のエネルギーを有する遅発$$gamma$$線に着目した遅発$$gamma$$線分光(DGS)法の技術開発を行っている。DGS法の確認試験として、PCDFにおいて、Pu溶液及びMOX粉末試料を用いた遅発$$gamma$$線測定試験を下記の4段階で実施することを計画している。(1)自発核分裂性核種由来の遅発$$gamma$$線測定(パッシブ測定)、(2)速中性子利用による遅発$$gamma$$線測定(アクティブ測定)、(3)DGSI(試料中の自発核分裂性核種由来の中性子作用による遅発$$gamma$$線)測定(パッシブ測定)、(4)熱中性子利用による遅発$$gamma$$線測定(パッシブ測定)。本報告では、PCDFで実施する核物質試料を用いたDGS試験計画について報告する。※本件は、今回のINMMにて開催される核不拡散用アクティブ中性子非破壊測定技術開発(実施窓口:ISCN)のシリーズ発表(全7件)のうち、ISCNから発表の依頼を受け、PCDFで実施する核物質試料を用いたDGS測定試験の目的及び具体的な試験方法について報告するものである。

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