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Development of an areal density imaging for boron and other elements

土川 雄介; 甲斐 哲也; 阿部 雄太; 及川 健一; Parker, J. D.*; 篠原 武尚; 佐藤 一憲

Journal of Physics; Conference Series, 2605, p.012022_1 - 012022_6, 2023/10



Introduction to Neutron Radiography Facilities at the Japan Research Reactor-3

栗田 圭輔; 飯倉 寛; 土川 雄介; 甲斐 哲也; 篠原 武尚; 大平 直也*; 伊藤 大介*; 齊藤 泰司*; 松林 政仁

Journal of Physics; Conference Series, 2605, p.012005_1 - 012005_6, 2023/10

2021年2月26日にJapan Research Ractor-3(JRR-3)の運転が再開され、2021年7月には利用運転が再開された。JRR-3の運転再開に伴い、TNRFとCNRFと呼ばれる2つのイメージング施設も利用を再開している。本発表では、これら2つの中性子施設の詳細について報告する。


Neutron resonance absorption imaging of simulated high-level radioactive waste in borosilicate glass

大場 洋次郎; 元川 竜平; 金子 耕士; 永井 崇之; 土川 雄介; 篠原 武尚; Parker, J. D.*; 岡本 芳浩

Scientific Reports (Internet), 13, p.10071_1 - 10071_8, 2023/06

 被引用回数:0 パーセンタイル:0.01

The spatial distribution of constituent elements in borosilicate glasses containing simulated high-level radioactive liquid waste (HLLW) was investigated using neutron resonance absorption imaging. The resonance absorption dips of Rh, Pd, Na, Gd, Cs, and Sm were detected in the neutron transmission spectra of the glass samples. The neutron transmission images at the resonance energies of these elements provided the spatial distributions within the glass samples. Rh and Pd led sedimentation, while Gd, Sm, and Cs were uniformly dispersed. These results clearly show the potential of neutron resonance absorption imaging for characterizing borosilicate glasses.


First measurement of differential cross sections and photon beam asymmetries for photoproduction of the $$f_0$$ (980) meson decaying into $$pi^0 pi^0$$ at $$E_gamma <$$ 2.4 GeV

村松 憲仁*; 土川 雄介; LEPS2 BGOegg Collaboration*; 他61名*

Physical Review C, 107(4), p.L042201_1 - L042201_5, 2023/04

For the first time, differential cross sections and photon beam asymmetries were measured for the reaction $$gamma p to f_0 (980) p to pi^0 pi^0 p$$ by using a linearly polarized photon beam up to 2.4 GeV and a liquid hydrogen target. The $$f_0$$ (980) photoproduction signal was clearly observed owing to the absence of contributions from vector-meson photoproduction. The results indicate the $$t$$-channel exchange of vector mesons as a mechanism of the $$f_0$$ (980) photoproduction at $$E_gamma$$ approximate to 2.1 GeV, putting constraints on the nature of $$f_0$$ (980).


Differential cross sections and photon beam asymmetries of $$eta$$ photoproduction on the proton at $$E_gamma$$ = 1.3-2.4 GeV

橋本 敏和*; 土川 雄介; LEPS BGOegg Collaboration*; 他58名*

Physical Review C, 106(3), p.035201_1 - 035201_15, 2022/09

 被引用回数:2 パーセンタイル:68.81(Physics, Nuclear)

We report exclusive measurements for the $$eta$$ photoproduction on a proton target. The differential cross sections and photon beam asymmetries of the $$gamma p to eta p$$ reaction are measured in a center-of-mass energy ($$W$$) range of 1.82-2.32 GeV and a polar angle range of $$-1.0 < cos theta_{c.m.}^eta < 0.6$$ by using a large acceptance calorimeter (BGOegg) and forward-angle charged-particle detectors at the SPring-8 LEPS2 beamline. The reaction is identified with a kinematic fitting method to select a recoil proton and two photons produced in an $$eta$$ meson decay. A bump structure at W = 2.0-2.3 GeV in the differential cross section is confirmed at extremely backward $$eta$$ polar angles, where the existing data are inconsistent with each other. This bump structure is likely associated with high-spin resonances that couple with $$sbar{s}$$ quarks. The photon beam asymmetries in a wide $$eta$$ polar angle range for the photon beam energies above 2.1 GeV are reported for the first time, providing an additional constraint to nucleon resonance studies at high energies.


Visualization of the boron distribution in core material melting and relocation specimen by neutron energy resolving method

阿部 雄太; 土川 雄介; 甲斐 哲也; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 大石 佑治*; 加美山 隆*; 永江 勇二; 佐藤 一憲

JPS Conference Proceedings (Internet), 33, p.011075_1 - 011075_6, 2021/03

Since the hardness of fuel debris containing boride from B$$_{4}$$C pellet in control rod is estimated to be two times higher as that of oxide, such as UO$$_{2}$$ and ZrO$$_{2}$$, distribution of such boride in the fuel debris formed in the Fukushima-Daiichi Nuclear Power Plants may affect the process of debris cutting and removal. The high neutron absorption of boron may affect the possibility of re-criticality during the process of debris removal. Therefore, boride distribution in fuel debris is regarded as an important issue to be addressed. However, boron tends to have difficult in quantification with conventionally applied methods like EPMA and XPS. In this study, accelerator-driven neutron-imaging system was applied. Since boron is the material for neutron absorption, its sensitivity in terms of neutron penetration through specimens is concerned. To adjust neutron attenuation of a specimen to suit a particular measurement by selecting the neutron energy range, we focused on the energy resolved neutron imaging system RADEN, which utilizes wide energy range from meV to keV. Development of a method to visualize boron distribution using energy-resolved neutrons has been started. In this presentation the authors show the status of the development of a method utilizing energy-resolved neutrons and provide some outcome from its application to the Core Material Melting and Relocation (CMMR)-0 and -2 specimens.


Feasibility study of PGAA for boride identification in simulated melted core materials

土川 雄介; 阿部 雄太; 大石 佑治*; 甲斐 哲也; 藤 暢輔; 瀬川 麻里子; 前田 亮; 木村 敦; 中村 詔司; 原田 正英; et al.

JPS Conference Proceedings (Internet), 33, p.011074_1 - 011074_6, 2021/03

福島原子力発電所の解体作業では、溶融した燃料棒に含まれるホウ素分布を事前に把握することが重要である。溶融燃料棒の模擬試験体を用意し、ホウ素やホウ化物の含有量を調査する研究が行われてきた。本研究では、その一環として中性子を用いたホウ素並びにホウ化物分布の測定技術開発を行った。ホウ素の中性子吸収に伴う即発ガンマ線を測定し、ホウ素量や二次元分布を測定した。また、n(B,$$alpha$$$$gamma$$)反応における478keV$$gamma$$線は、ホウ素の化合状態により、$$gamma$$線ピークの幅が変化することが知られている。このことを用い、特に溶融燃料棒周辺に存在することが予測されているZrBやFeBといったホウ化物の識別可能性について調査した。測定はJ-PARC/MLFのANNRI, NOBORU, RADENにて行った。これらの解析結果について報告する。


Measurement of Doppler broadening of prompt gamma-rays from various zirconium- and ferro-borons

土川 雄介; 甲斐 哲也; 阿部 雄太; 大石 佑治*; Sun, Y.*; 及川 健一; 中谷 健; 佐藤 一憲

Nuclear Instruments and Methods in Physics Research A, 991, p.164964_1 - 164964_5, 2021/03

 被引用回数:0 パーセンタイル:19.67(Instruments & Instrumentation)



Pulsed neutron imaging for differentiation of ice and liquid water towards fuel cell vehicle applications

樋口 雄紀*; 瀬戸山 大吾*; 伊勢川 和久; 土川 雄介; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 長井 康貴*

Physical Chemistry Chemical Physics, 23(2), p.1062 - 1071, 2021/01

 被引用回数:5 パーセンタイル:54.2(Chemistry, Physical)



Differential cross sections, photon beam asymmetries, and spin density matrix elements of $$omega$$ photoproduction off the proton at $$E_gamma$$ = 1.3-2.4 GeV

村松 憲仁*; 土川 雄介; LEPS2/BGOegg Collaboration*; 他59名*

Physical Review C, 102(2), p.025201_1 - 025201_10, 2020/08

 被引用回数:7 パーセンタイル:70.75(Physics, Nuclear)

For the reaction $$gamma p to omega p$$, differential cross sections, photon beam asymmetries, and spin density matrix elements have been measured in the BGOegg experiment at the SPring-8 LEPS2 beamline by using a large acceptance electromagnetic calorimeter. A 1.3-2.4 GeV photon beam with high linear polarization has enabled a precision measurement of photon beam asymmetries $$Sigma$$ and polarized spin density matrix elements $$rho^1_{1-1}$$ over a wide angular range, especially above the total energy of about 2 GeV for the first time. The measured $$rho^1_{1-1}$$ indicates the dominance of $$s$$-channel resonances even at higher energies. The $$Sigma$$ values at backward angles are not reproduced by the existing partial-wave analysis in the highest-energy region, providing new constraints to the contribution of nucleon resonances with high spins.


Development of three-dimensional distribution visualization technology for boron using energy resolved neutron-imaging system (RADEN)

阿部 雄太; 土川 雄介; 甲斐 哲也; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 大石 佑治*; 加美山 隆*; 永江 勇二; 佐藤 一憲

Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08

Boron carbide is used as a neutron-absorbing material in Fukushima-Daiichi Nuclear Power Station (1F), producing borides that are twice as hard as oxides (such as UO$$_{2}$$ and ZrO$$_{2}$$). The high neutron absorption of boron affects the evaluation of re-criticality during the process of debris retrieval. Therefore, it is important not only to determine the presence of boron but also to investigate the distribution of boron inside the material in a non-destructive manner during decommissioning. To address the uncertainties in the core material relocation behavior of boiling water reactor (BWR) during a severe accident (SA), solidified melt specimens of a simulated fuel assembly were prepared by plasma heating. If core material melting and relocation (CMMR) specimens can be used to estimate the B distribution in 1F Unit-3, that will provide valuable information in the decommissioning of 1F. To address this, the authors focused on the energy-resolved neutron imaging system, RADEN, which utilizes a wide energy range, from meV to keV. This is an innovative three-dimensional analysis technology for boride distribution that affects the evaluation of hardness and re-criticality. In the calibration standard samples (Zr$$_{x}$$B$$_{1-x}$$ and Fe$$_{x}$$B$$_{1-x}$$), there was a good correlation between boron concentration and the energy-dependence of the cross sections of cold and epi-thermal neutrons. In the CMMR specimens, boron distribution was confirmed from the contrast difference between cold and epi-thermal neutrons. In the future, the results of calibration standard samples will be applied to the results of CMMR specimens. With this method, three-dimensional boron distribution will be measured, and the understanding of boride distribution 1F Unit-3 will be improved, which may be reflected in an improved SA code.


$$omega N$$ scattering length from $$omega$$ photoproduction on the proton near the reaction threshold

石川 貴嗣*; 藤村 寿子*; 深澤 宏司*; 橋本 亮*; He, Q.*; 本多 佑記*; 保坂 淳; 岩田 高広*; 甲斐田 俊*; 笠木 治郎太*; et al.

Physical Review C, 101(5), p.052201_1 - 052201_6, 2020/05

Photoproduction of the omega meson on the proton has been experimentally studied near the threshold. The total cross sections are determined at incident energies ranging from 1.09 to 1.15 GeV. The 1/2 and 3/2 spin-averaged scattering length $$a$$$$_{omega p}$$ and effective range $$r$$$$_{omega p}$$ between the CO meson and proton are estimated from the shape of the total cross section as a function of the incident photon energy: $$a$$$$_{omega p}$$ = (-0.97 $$_{rm -0.16stat-0.00syst}^{rm +0.16stat+0.03syst}$$ + $$i$$(0.07 $$_{rm -0.14stat-0.09syst}^{rm +0.15stat+0.17syst}$$) fm and $$r$$$$_{omega p}$$ = (+2.78 $$_{rm -0.54stat-0.12syst}^{rm +0.67stat+0.11syst}$$) + $$i$$(-0.01 $$_{rm -0.50stat-0.00syst}^{rm +0.46stat+0.06syst}$$) fm, resulting in a repulsive force. The real and imaginary parts for $$a$$$$_{omega p}$$ and $$r$$$$_{omega p}$$ are determined separately for the first time. A small $$P$$-wave contribution does not affect the obtained values.


Search for $$eta$$' bound nuclei in the $$^{12}$$C($$gamma,p$$) reaction with simultaneous detection of decay products

冨田 夏希*; 土川 雄介; LEPS2/BGOegg Collaboration*; 他61名*

Physical Review Letters, 124(20), p.202501_1 - 202501_7, 2020/05

 被引用回数:7 パーセンタイル:62.96(Physics, Multidisciplinary)

We measured missing mass spectrum of the $$^{12}$$C($$gamma,p$$) reaction for the first time in coincidence with potential decay products from $$eta^prime$$ bound nuclei. We tagged an $$(eta + p)$$ pair associated with the $$eta^prime N to eta N$$ process in a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed in the bound-state region. An upper limit of the signal cross section was obtained to be 2.2~nb/sr at the 90% confidence level. It is compared with theoretical cross sections, whose normalization ambiguity is suppressed by measuring a quasifree $$eta^prime$$ production rate. Our results indicate a small branching fraction of the $$eta^prime N to eta N$$ process and/or a shallow $$eta^prime$$-nucleus potential.


$$eta N$$ scattering parameters and possible $$eta^prime d$$ bound state from $$eta$$ photoproduction on the deuteron

石川 貴嗣*; 土川 雄介; FOREST Collaboration*; 他48名*

Acta Physica Polonica B, 51(1), p.27 - 32, 2020/00

 被引用回数:0 パーセンタイル:0(Physics, Multidisciplinary)

Two physics programs, determination of low-energy scattering parameters between the eta meson ($$eta$$) and nucleon ($$N$$), and search for a possible bound state between the eta prime meson ($$eta^prime$$) and deuteron ($$d$$), using $$eta$$ photoproduction from the deuteron target are conducted at ELPH, Tohoku University. An experiment is carried out to determine the low-energy $$eta N$$ scattering parameters using a special kinematics. The measurement is currently in progress to determine the real part of the $$eta$$-neutron ($$n$$) scattering length. A possible $$eta^prime d$$ bound state is theoretically predicted, and a structure corresponding to the state can be observed via the $$gamma d to eta d$$ reaction at incident energies around 1.2 GeV. The angular differential cross sections are determined at backward $$eta$$ emission angles. The tail of the corresponding peak is not observed, and the background level is much higher than predicted.


Measurement of neutron scattering cross section of nano-diamond with particle diameter of approximately 5 nm in energy range of 0.2 meV to 100 meV

勅使河原 誠; 土川 雄介*; 市川 豪*; 高田 慎一; 三島 賢二*; 原田 正英; 大井 元貴; 河村 幸彦*; 甲斐 哲也; 河村 聖子; et al.

Nuclear Instruments and Methods in Physics Research A, 929, p.113 - 120, 2019/06

 被引用回数:15 パーセンタイル:86.52(Instruments & Instrumentation)

ナノダイアモンドは、冷中性子以下のエネルギーにおける反射材として注目されている。ナノダイアモンドを用いた中性子源の高度化には、断面積データの整備が必要である。そのため、この論文では、中性子の透過率の測定から0.2meVから100meVの範囲で全断面積を測定した結果を報告する。測定した全断面積は、エネルギーが低くなるにつれて大きくなり、グラファイトと比較すると0.2meVで約2桁以上高くなることが分かった。その全断面積に占める非弾性散乱の寄与を調べるため、中性子のエネルギー1.2, 1.5, 1.9及び5.9meVで中性子非弾性散乱実験を行った。その結果、測定したエネルギーにおいて、全断面積に占める非弾性散乱の寄与がほぼ無視できることも分かった。さらに、中性子小角散乱実験の結果から、全断面積の高くなる要因として、前方方向、いわゆる小角方向への散乱の寄与が高いことが示された。


Fast neutron imaging capability at NOBORU and RADEN of J-PARC

土川 雄介; 甲斐 哲也; 篠原 武尚; Parker, J. D.*; 及川 健一

no journal, , 

J-PARC MLFの中性子ビームラインNOBORU及びRADENにおける高速中性子を用いた中性子イメージングについて議論する。また0.5eV$$sim$$MeVの中性子を用いた最近の中性子イメージングの研究成果や検出器開発について報告する。


Activities of neutron resonance absorption imaging in J-PARC

甲斐 哲也; 土川 雄介; 廣井 孝介; Su, Y. H.; 瀬川 麻里子; Parker, J. D.*; 松本 吉弘*; 林田 洋寿*; 篠原 武尚; 及川 健一

no journal, , 

Neutron resonance absorption imaging is a technique to visualize spatial distributions of specific elements in a sample. A neutron cross section rapidly increases at resonance energies specified by a target element. The resonance peaks in the cross section are measured as sharp dips in an energy-dependent neutron transmission rate of a sample. In an imaging measurement the transmission rate at each position is measured by a two-dimensional time-analyzing neutron detector, and a transmission image enhancing a specific element is obtained at its resonance energies determined by the flight time of neutron. It is also possible to visualize a distribution of temperature of an element by analyzing the sharp dips broadened by the Doppler effect caused by thermal vibration of the element. In this presentation, research activities using the neutron resonance absorption imaging technique performed in NOBORU and RADEN are introduced.


Development of energy-resolved neutron imaging at RADEN in J-PARC MLF

篠原 武尚; 甲斐 哲也; 及川 健一; 廣井 孝介; Su, Y. H.; 中谷 健; 關 義親; 土川 雄介; 林田 洋寿*; Parker, J. D.*; et al.

no journal, , 




土川 雄介; 阿部 雄太; 大石 佑治*; 甲斐 哲也; 原田 正英; 及川 健一; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 永江 勇二; et al.

no journal, , 

福島第一原子力発電所の解体作業では、溶融、再凝固した燃料棒等に含まれるホウ素分布を調査する必要がある。本研究では、中性子を用いたホウ素並びにホウ化物の空間分布測定技術開発を行った。ホウ素の中性子吸収に伴う即発ガンマ線を測定し、ホウ素量やその二次元分布を測定した。また、n(B,$$alpha$$$$gamma$$)反応における478keV$$gamma$$線を用いて即発ガンマ線解析(PGAA)を行い、測定したピーク幅の情報から、特に溶融燃料棒やその周辺に存在することが予測されているZrBやFeBといったホウ化物が分離可能であることが測定結果から示唆された。J-PARC/MLFのNOBORU, RADENビームラインで行った測定と今後の課題、展望について報告、議論する。



阿部 雄太; 甲斐 哲也; 土川 雄介; 松本 吉弘*; Parker, J. D.*; 篠原 武尚; 大石 佑治*; 加美山 隆*; 永江 勇二; 佐藤 一憲

no journal, , 


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