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Neutron capture cross-section measurement by mass spectrometry for Pb-204 irradiated in JRR-3

中村 詔司; 芝原 雄司*; 木村 敦; 遠藤 駿典; 静間 俊行*

Journal of Nuclear Science and Technology, 60(9), p.1133 - 1142, 2023/09

 被引用回数:0 パーセンタイル:0.02(Nuclear Science & Technology)



Measurement of the spatial polarization distribution of circularly polarized gamma rays produced by inverse Compton scattering

平 義隆*; 遠藤 駿典; 河村 しほり*; 南部 太郎*; 奥泉 舞桜*; 静間 俊行*; Omer, M.; Zen, H.*; 岡野 泰彬*; 北口 雅暁*

Physical Review A, 107(6), p.063503_1 - 063503_10, 2023/06

 被引用回数:0 パーセンタイル:0.01(Optics)



Accurate estimation of spectral density of LCS gamma-ray source

Omer, M.; 静間 俊行*; 羽島 良一*; 小泉 光生

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), 3 Pages, 2022/11

Gamma-rays originated from laser Compton scattering (LCS) are convenient photon sources for nondestructive interrogation of nuclear materials. LCS can be used with nuclear resonance fluorescence (NRF) and X-ray fluorescence (XRF), the two of which are considered photon-based active interrogation techniques. However, an accurate estimation of the incident LCS $$gamma$$-ray flux is crucial. The $$gamma$$-ray flux is customarily measured using high purity germanium (HPGe) detectors, usually calibrated using standard point-like radioactive $$gamma$$-ray sources. These standard sources are entirely different from LCS beams in terms of detection geometry. Therefore, the calibration process must be corrected to meet the LCS beam conditions. Here, we demonstrate how to implement the required corrections and provide experimental validation of these corrections.


Low-lying dipole strength distribution in $$^{204}$$Pb

静間 俊行*; 遠藤 駿典; 木村 敦; Massarczyk, R.*; Schwengner, R.*; Beyer, R.*; Hensel, T.*; Hoffmann, H.*; Junghans, A.*; R$"o$mer, K.*; et al.

Physical Review C, 106(4), p.044326_1 - 044326_11, 2022/10

 被引用回数:0 パーセンタイル:0.02(Physics, Nuclear)



Calculating off-axis efficiency of coaxial HPGe detectors by Monte Carlo simulation

Omer, M.; 静間 俊行*; 羽島 良一*; 小泉 光生

Radiation Physics and Chemistry, 198, p.110241_1 - 110241_7, 2022/09

 被引用回数:1 パーセンタイル:49.42(Chemistry, Physical)

In beam geometries where a directed $$gamma$$-ray beam hits the surface of a coaxial high purity germanium detector (HPGe), the detector efficiency is sensitive to the position where $$gamma$$-rays initially hit the detector surface because the structure of the detector is nonuniform. This may cause inaccuracy of the detector efficiency when measured using standard sources that are point-like sources emitting $$gamma$$-rays isotropically. Obtaining a precise estimation of the full energy peak efficiency of the coaxial HPGe detector in the beam geometry for on-axis and off-axis measurements requires a Monte Carlo simulation. We performed a Monte Carlo simulation that calculates the detector efficiency in the beam geometry. The effects of the off-axis distance and $$gamma$$-ray beam size on the efficiency are quantitatively analyzed. We found that the intrinsic efficiency in the beam geometry is maximized when the beam hits the detector at specific off-axis distances. Our Monte Carlo calculations have been supported by a nuclear resonance fluorescence experiment using laser Compton scattering $$gamma$$-ray beam.


Evaluation of analyzing power of gamma-ray polarimeter

遠藤 駿典; 静間 俊行*; Zen, H.*; 平 義隆*; Omer, M.; 河村 しほり*; 安部 亮太*; 奥平 琢也*; 北口 雅暁*; 清水 裕彦*

UVSOR-49, P. 38, 2022/08

To measure the circular polarization of gamma-rays, the gamma-ray polarimeter was developed. The analyzing power of the polarimeter was measured using circularly polarized gamma-rays in UVSOR BL1U. Magnetic hysteresis of the polarimeter was also observed. The analyzing power was obtained as 2.12$$pm$$0.04%.


Isomer production ratio of the $$^{112}$$Cd($$n,gamma$$)$$^{113}$$Cd reaction in an $$s$$-process branching point

早川 岳人*; 藤 暢輔; 木村 敦; 中村 詔司; 静間 俊行*; 岩本 信之; 千葉 敏*; 梶野 敏貴*

Physical Review C, 103(4), p.045801_1 - 045801_5, 2021/04

 被引用回数:0 パーセンタイル:0.02(Physics, Nuclear)

A $$beta$$-decay unstable isomer with a half-life of 14.1 y at 264 keV in $$^{113}$$Cd is a branching point in the $$s$$ process, from which a weak branch reaches to a rare tin isotope $$^{115}$$Sn whose astrophysical origin has been an open problem. We have measured $$gamma$$ rays decaying to the ground state or the isomer in the $$^{112}$$Cd($$n,gamma$$)$$^{113}$$Cd reaction using high-energy resolution detectors in conjunction with a time-of-flight method. The relative production ratios of the isomer to the total following the neutron capture reactions on $$^{112}$$Cd have been evaluated in an energy region of up to 9 keV, and the spin and parity of several resonances have been assigned.


High-spin states in $$^{35}$$S

郷 慎太郎*; 井手口 栄治*; 横山 輪*; 青井 考*; Azaiez, F.*; 古高 和禎; 初川 雄一; 木村 敦; 木佐森 慶一*; 小林 幹*; et al.

Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03

 被引用回数:4 パーセンタイル:66.92(Physics, Nuclear)

Excited states in $$^{35}$$S were investigated by in-beam $$gamma$$-ray spectroscopy using the $$^{26}$$Mg($$^{18}$$O, 2$$alpha$$1$$n$$) fusion-evaporation reaction. The de-exciting $$gamma$$-rays were measured with germanium detector arrays along with the measurement of evaporated charged particles in a $$4pi$$ segmented Si detector array. The level scheme was extended up to 12470 keV. The obtained level structure is compared with the large-scale shell-model calculations. The possibility of isoscalar-pair excited states is discussed for $$J=(17/2)$$ states with comparison between the experimental and theoretical results.


Low-lying electric and magnetic dipole strengths in $$^{207}$$Pb

静間 俊行*; 湊 太志; Omer, M.*; 早川 岳人*; 大垣 英明*; 宮本 修治*

Physical Review C, 103(2), p.024309_1 - 024309_8, 2021/02


 被引用回数:4 パーセンタイル:66.92(Physics, Nuclear)



Compton scattering of quasi-monochromatic $$gamma$$-ray beam

Omer, M.; 静間 俊行*; 羽島 良一*

Nuclear Instruments and Methods in Physics Research A, 951, p.162998_1 - 162998_6, 2020/01

 被引用回数:1 パーセンタイル:16.1(Instruments & Instrumentation)

Compton scattering of a single-energy $$gamma$$-ray results in a one-to-one relationship between the incident and scattered photon energies. This relationship is altered when the incident beam has a definite energy distribution because of the broadening occurring in the energy distribution upon Compton scattering. This broadening causes a change in the spectral density of the Compton-scattered spectra. To restore the spectral density, the energy distribution of the scattered radiation must be manifested as a function of the scattering kinematics. Here, we propose a simple analytic way to calculate the energy spread of the scattered photons in terms of the geometry of the scattering process and the energy spread of the incident photon beam. The predictions of the model agree with measurements of Compton scattering of quasi-monochromatic $$gamma$$-ray beams, carried out at the High Intensity $$gamma$$-ray Source (HI$$gamma$$S) facility, Duke University. As a benchmark of our method, we measured the intensity profile of energy-distributed $$gamma$$-ray beams by direct measurements as well as by Compton scattering. We found that only when the spectral density of the scattered radiation is restored, the measured intensity profile agrees with the actual profile of the incident beam. The proposed method can continuously measure the flux of an energy-distributed $$gamma$$-ray beams in the real time and on a bin-by-bin basis. Such online monitoring of $$gamma$$-ray beams is indispensable for in-beam measurements and applications. This work was 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.


Testing enrichment meter based on nuclear resonance fluorescence

Omer, M.; 静間 俊行*; 羽島 良一*; 小泉 光生

日本核物質管理学会第40回年次大会プロシーディングス集, p.59 - 62, 2019/11

Nuclear resonance fluorescence (NRF) is a phenomenon that a nuclide-specific $$gamma$$-ray is resonantly absorbed and re-emitted. This method is considered useful for the nondestructive detection of nuclear materials. In order to demonstrate how accurate the NRF method is able to measure the isotopic abundance, we performed NRF experiments on natural tungsten as a surrogate of nuclear materials at the High Intensity $$gamma$$-ray Source (HI$$gamma$$S) facility, Duke University. Our results show that the relative deviations between the reference and measured abundances are less than $$pm$$ 4%. This work was 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.


Spin and parity determination of the 3.004-MeV level in $$^{27}$$Al; Its low-lying multiplet structure

静間 俊行*; Omer, M.; 羽島 良一*; 清水 則孝*; 宇都野 穣

Physical Review C, 100(1), p.014307_1 - 014307_6, 2019/07

 被引用回数:6 パーセンタイル:58.25(Physics, Nuclear)

Nuclear resonance fluorescence (NRF) is a promising technique for the nondestructive assay (NDA) of nuclear materials. One of the features of the NRF is the angular distribution of the emitted photons in response to a linearly polarized incident beam. Here we irradiate the calibration standard of $$^{27}$$Al to linearly polarized beam. The spin and parity of the 3.004-MeV level in $$^{27}$$Al have been determined by measuring the angular correlation function of radiation emitted from levels populated by resonant absorption of polarized photons. The nuclear resonance fluorescence experiments were carried out at the High Intensity $$gamma$$-ray Source (HI$$gamma$$S) facility at Duke University using quasi-monoenergetic linearly polarized photon beams. The spin and parity of levels in $$^{27}$$Al were deduced from a comparison of the measured angular distribution ratios and azimuthal intensity asymmetries with theoretical predictions. The observed resonance properties were compared with shell model calculations using the universal sd interaction. The Monte Carlo shell model calculations were also performed to investigate low-energy structure of $$^{27}$$Al. This work was 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.


Dipole strength distribution in $$^{206}$$Pb for the evaluation of the neutron capture cross section of $$^{205}$$Pb

静間 俊行; 岩本 信之; 牧永 あや乃*; Massarczyk, R.*; Schwengner, R.*; Beyer, R.*; Bemmerer, D.*; Dietz, M.*; Junghans, A.*; K$"o$gler, T.*; et al.

Physical Review C, 98(6), p.064317_1 - 064317_12, 2018/12

 被引用回数:9 パーセンタイル:65.04(Physics, Nuclear)



Evaluation of neutron capture cross section on $$^{205}$$Pb with photonuclear data

岩本 信之; 静間 俊行*

EPJ Web of Conferences, 178, p.06004_1 - 06004_3, 2018/05

 被引用回数:0 パーセンタイル:0

Transmutation and reduction of high level radioactive wastes (e.g. minor actinides) produced in nuclear reactors are expected by an accelerator driven system (ADS). Japan Atomic Energy Agency proposed that Pb and Bi are used as a spallation target and coolant. The neutronics design was performed without including $$^{205}$$Pb, which is a long-lived radioactive nuclide with half-life of 1.7$$times$$10$$^{7}$$ years and thus has long-lasting radiotoxicity. $$^{205}$$Pb is produced by the neutron capture reaction on $$^{204}$$Pb. In order to evaluate the accumulated amount of $$^{205}$$Pb, the neutron capture cross section of $$^{205}$$Pb is needed. However, it has not been measured in the keV to MeV neutron energy region. In the present work the calculations of cross sections were performed by the nuclear reaction calculation code, CCONE. Measured photonuclear data of ($$gamma$$,$$gamma$$) reaction and photoneutron cross sections were used to evaluate photon strength function of $$^{206}$$Pb. The ($$gamma$$,$$gamma$$) reaction data used were newly obtained by an experiment at HZDR. The fixed photon strength function was applied to calculate the neutron capture cross sections of $$^{205}$$Pb. The resulting cross section is smaller than the data of $$^{204}$$Pb in the relevant energy region.


Low-lying dipole strength in $$^{52}$$Cr

静間 俊行*; 早川 岳人*; 大東 出*; 大垣 英明*; 宮本 修治*; 湊 太志

Physical Review C, 96(4), p.044316_1 - 044316_10, 2017/10

 被引用回数:8 パーセンタイル:57.93(Physics, Nuclear)

準単色線形偏向光子ビームを用いた核共鳴蛍光散乱実験によって、$$^{52}$$Crの低エネルギー双極子強度を測定した。励起状態のパリティは、入射光子ビームの偏極面における共鳴散乱$$gamma$$線の非対称性により決定した。励起エネルギー7.5MeVから12.1MeVまでの磁気双極子(M1)強度の総和は$$sum B(M1)uparrow=5.64(34) mu_N^2$$、電気双極子(E1)強度は$$sum B(E1)uparrow=73.7(23) times 10^{-3} e^2$$ fm$$^2$$という結果が得られた。観測されたM1とE1強度はSkyrme力を用いた乱雑位相近似法計算と比較を行い、双極子強度分布に対する2粒子2空孔状態とテンソル力の影響を調べた。この結果、2粒子2空孔状態とテンソル力の効果がともに、実験データの遷移強度の和を説明するために必要であることが分かった。


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



Proposal for selective isotope transmutation of long-lived fission products using quasi-monochromatic $$gamma$$-ray beams

早川 岳人; 宮本 修治*; 羽島 良一; 静間 俊行; 天野 壮*; 橋本 智*; 三澤 毅*

Journal of Nuclear Science and Technology, 53(12), p.2064 - 2071, 2016/12

 被引用回数:5 パーセンタイル:45.26(Nuclear Science & Technology)

準単色の$$gamma$$線による光核反応を用いた選択的な同位体変換法を提案する。この手法は、$$^{93}$$Zr, $$^{107}$$Pd、ないし$$^{79}$$Seのような長寿命核分裂生成物(LLFP)の粒子閾値が、同じ元素の他の安定同位体の粒子閾値より低いという事実に基づく。そのため、この手法では、ターゲット物質がLLFP以外に安定同位体を含んでいたとしても、新しくLLFPが生成されないという傑出した特徴を有する。レーザーコンプトン散乱$$gamma$$線と原子炉の中性子捕獲反応$$gamma$$線がこの手法に適した$$gamma$$線源である。


Measurement of the isomer production ratio for the $$^{112}$$Cd($$n,gamma$$)$$^{113}$$Cd reaction using neutron beams at J-PARC

早川 岳人*; 藤 暢輔; Huang, M.; 静間 俊行*; 木村 敦; 中村 詔司; 原田 秀郎; 岩本 信之; 千葉 敏*; 梶野 敏貴*

Physical Review C, 94(5), p.055803_1 - 055803_6, 2016/11

 被引用回数:4 パーセンタイル:34.89(Physics, Nuclear)

The astrophysical origin of a rare isotope $$^{115}$$Sn has remained still an open question. An isomer ($$T_{1/2}$$=14.1 y) in $$^{113}$$Cd is an s-process branching point from which a nucleosynthesis flow reaches to $$^{115}$$Sn. The $$s$$-process abundance of $$^{115}$$Sn depends on the isomer production ratio in the $$^{112}$$Cd($$n,gamma$$)$$^{113}$$Cd reaction. However, the ratio has not been measured in an energy region higher than the thermal energy. We have measured $$gamma$$ rays following neutron capture reactions on $$^{112}$$Cd using two cluster HPGe detectors in conjunction with a time-of-flight method at J-PARC. We have obtained the result that the relative $$gamma$$-ray intensity ratio of the isomer is almost constant in an energy region of up to 5 keV. This result suggests that the $$s$$-process contribution to the solar abundance of $$^{115}$$Sn is negligibly small. We have found that the ratio of a resonance at 737 eV shows about 1.5 times higher than other ratios. This enhancement can be explained by a $$p$$-wave neutron capture. This result suggests measurements of decay $$gamma$$ rays to isomers are effective to assign the spin and parity for neutron capture resonances.


Branching and fragmentation of dipole strength in $$^{181}$$Ta in the region of the scissors mode

Angell, C.; 羽島 良一; 静間 俊行; Ludewigt, B.*; Quiter, B. J.*

Physical Review Letters, 117(14), p.142501_1 - 142501_5, 2016/09

 被引用回数:7 パーセンタイル:50.3(Physics, Multidisciplinary)

In recent measurements of the scissors mode in radiative decay experiments, transition strengths were observed that were double that expected from theory and systematics well established from measurements on the radiative excitation channel, that is, using nuclear resonance fluorescence (NRF). Additional strength as measured with NRF can only present itself as heretofore unobserved branching or fragmentation of the scissors mode. Such a possibility was investigated in a transmission NRF measurement on the deformed, odd-mass $$^{181}$$Ta, using a quasi-monoenergetic $$gamma$$-ray beam at two beam energies, and additionally informing applications using transmission NRF to assay or detect odd-mass fissile isotopes. An anomalously large branching, $$approx$$70%, of small resonances to excited states was discovered. In contrast, previous studies using NRF of the scissors-mode strength in odd-mass nuclei assumed no branching existed. This branching, if present at all energies, combined with the observed highly-fragmented elastic strength would reconcile the scissors-mode strength observed in NRF measurements with the expectations for enhanced scissors-mode strength from radiative decay experiments.


Simulation of the elastic scattering contributions to the NRF-based nondestructive assay of nuclear materials

Omer, M.; 羽島 良一*; Angell, C.*; 静間 俊行*; 早川 岳人*; 瀬谷 道夫; 小泉 光生

Proceedings of INMM 57th Annual Meeting (Internet), 9 Pages, 2016/07


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