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Journal Articles

Structural change of borosilicate glass by boron isotope composition

Nagai, Takayuki; Okamoto, Yoshihiro; Akiyama, Daisuke*; Uehara, Akihiro*; Fujii, Toshiyuki*; Sekimoto, Shun*

KURNS Progress Report 2019, P. 257, 2020/08

To understand the influence of glass structural change by neutron irradiation and boron isotope composition, glass samples were made from enrichment boric acid reagents and neutron irradiation of those samples was carried out in Pn-2 of KUR. The structural change of glass sample after the irradiation will be estimated in 2020FY. Before neutron irradiation test of glass samples, the Si-O bridging structure difference by boron isotope composition compared by using a Raman spectrometry.

Journal Articles

Effects of the nuclear structure of fission fragments on the high-energy prompt fission $$gamma$$-ray spectrum in $$^{235}$$U($$n_{rm th},f$$)

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.; Ogawa, Tatsuhiko; Soldner, T.*; K$"o$ster, U.*; Pollitt, A.*; Hambsch, F.-J.*; et al.

Physical Review C, 100(4), p.044610_1 - 044610_7, 2019/10

 Times Cited Count:2 Percentile:63.02(Physics, Nuclear)

Journal Articles

Structural change of borosilicate glass by neutron irradiation

Nagai, Takayuki; Kobayashi, Hidekazu; Okamoto, Yoshihiro; Akiyama, Daisuke*; Sato, Nobuaki*; Uehara, Akihiro*; Fujii, Toshiyuki*; Sekimoto, Shun*

KURNS Progress Report 2018, P. 105, 2019/08

To understand this structural change of a borosilicate glass by a neutron irradiation in detail, the irradiation test was carried out in KUR in 2017FY. The glass structure was estimated by using Raman spectrometry in 2018FY. Comparing with the Raman spectra of glass samples before and after irradiation, it could be observed the change of peak height of Si-O bridging structure by the irradiation.

Journal Articles

A New detector system for the measurement of high-energy prompt $$gamma$$-rays for low-energy neutron induced fission

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.*; Ogawa, Tatsuhiko; Soldner, T.*; Hambsch, F.-J.*; A$"i$che, M.*; Astier, A.*; et al.

Nuclear Instruments and Methods in Physics Research A, 906, p.88 - 96, 2018/10

 Times Cited Count:3 Percentile:40.19(Instruments & Instrumentation)

We have developed a new setup to measure prompt fission $$gamma$$-ray spectra in neutron induced fission up to energies sufficient to reveal the structure associated with giant dipole resonances of fission fragments. The setup consists of multi-wire proportional counters, to detect both fission fragments in coincidence, and two large volume (101.6 mm in diameter and 127.0 mm in length) LaBr$$_{3}$$(Ce) scintillators, to measure the $$gamma$$-rays. The setup was used to obtain the prompt fission $$gamma$$-ray spectrum for thermal neutron induced fission of $$^{235}$$U at the PF1B cold-neutron beam facility of the Institut Laue-Langevin, Grenoble, France. We have successfully measured the $$gamma$$-ray spectrum up to energies of about 20 MeV, what extends the currently known $$gamma$$-ray spectrum limit to higher energies by approximately a factor of two.

Journal Articles

Measurements of the neutron activation cross sections for Bi and Co at 386 MeV

Yashima, Hiroshi*; Sekimoto, Shun*; Ninomiya, Kazuhiko*; Kasamatsu, Yoshitaka*; Shima, Tatsushi*; Takahashi, Naruto*; Shinohara, Atsushi*; Matsumura, Hiroshi*; Satoh, Daiki; Iwamoto, Yosuke; et al.

Radiation Protection Dosimetry, 161(1-4), p.139 - 143, 2014/10

 Times Cited Count:2 Percentile:77.88(Environmental Sciences)

The neutron activation cross sections up to GeV are important for the neutron dosimetry of the radiation field in high-energy and high-intensity accelerator facilities for a project of intense spallation neutron source. But the evaluation of neutron activation cross section data is not enough above 20 MeV because experimental data are still scarce. This study aimed to measure the neutron activation cross sections of Bi and Co by using a quasi-monoenergetic neutron field. In this symposium, we will present obtained experimental cross section data with the other experimental data (neutron-induced and proton-induced), the calculated data by PHITS code and the evaluated nuclear data.

Journal Articles

Activation detector measurements at the hadron absorber of the NuMI neutrino beamline at Fermilab

Matsuda, Norihiro; Kasugai, Yoshimi; Matsumura, Hiroshi*; Iwase, Hiroshi*; Toyoda, Akihiro*; Yashima, Hiroshi*; Sekimoto, Shun*; Oishi, Koji*; Sakamoto, Yukio*; Nakashima, Hiroshi; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.337 - 340, 2014/04

The Neutrinos at the Main Injector (NuMI) at Fermilab produces intense neutrino beam to investigate the phenomena of the neutrino mixing and oscillation. The Hadron Absorber, consists of thick blocks of aluminum, iron and concrete, is placed at the end of decay volume as a dump for primary proton and secondary particles generated in NuMI. In order to estimate the shielding effect, the reaction rate measurements with activation detector were carried out on the back surface of the absorber. The induced activities in the detectors were measured by analyzing their $$gamma$$-ray spectra using HPGe detectors. Two kind of peak was showed on two-dimensional distributions of obtained reaction rates at right angle to the beam direction. One was strong peaks at the both horizontal side. And, another smaller was at the top. It was concluded that these peaks were the results of particles streaming through the gaps in the Hadron Absorber shielding.

Journal Articles

Actinide-handling experience for training and education of future expert under J-ACTINET

Osaka, Masahiko; Konashi, Kenji*; Hayashi, Hirokazu; Li, D.*; Homma, Yoshiya*; Yamamura, Tomoo*; Sato, Isamu; Miwa, Shuhei; Sekimoto, Shun*; Kubota, Takumi*; et al.

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12

Summer schools for future experts have successfully been completed under Japan Actinide Network (J-ACTINET) for the purpose of development of human resources who are expected to be engaged in every areas of actinide-research/engineering. The first summer school was held in Ibaraki-area in August 2009, followed by the second one in Kansai-area in August 2010. Two summer schools have focused on actual experiences of actinides in actinide-research fields for university students and young researchers/engineers as an introductory course of actinide-researches. Several quasi actinide-handling experiences at the actinide-research fields have attracted attentions of participants at the first school in Ibaraki-area. The actual experiments using actinides-containing solutions have been carried out at the second school in Kansai-area. Future summer schools will be held every year for the sustainable human resource development in various actinide-research fields.

Journal Articles

Coordination characteristics of trivalent lanthanides and actinides in molten hydrate salts of Ca(NO$$_3$$)$$_2$$ and CaCl$$_2$$

Fujii, Toshiyuki*; Okude, Genki*; Uehara, Akihiro*; Sekimoto, Shun*; Hayashi, Hirokazu; Akabori, Mitsuo; Minato, Kazuo; Yamana, Hajimu*

Journal of Radioanalytical and Nuclear Chemistry, 288(1), p.181 - 187, 2011/04

 Times Cited Count:4 Percentile:61.89(Chemistry, Analytical)

Distribution behavior of Ce(III), Am(III), and Cm(III) between tri-n-butyl phosphate solution and molten calcium nitrate hydrate Ca(NO$$_3$$)$$_2cdotmathit{R}$$H$$_2$$O or molten calcium chloride hydrate CaCl$$_2cdotmathit{R}$$H$$_2$$O was studied radiochemically. In Ca(NO$$_3$$)$$_2cdotmathit{R}$$H$$_2$$O systems, maximum separation factors of Ce and Cm to Am were observed to be 12 (Ce/Am) and 1.7 (Cm/Am). The distribution ratios of these elements increased with the decrease of water activity in the hydrates, and the extractabilities at the water deficient region was less sensitive compared to those at the water abundant region. This trend was similar to the coordination circumstance change observed in electronic absorption spectra of Nd(III) in the hydrates.

Journal Articles

Measurement of neutron cross sections for yttrium and terbium at 287 MeV

Sekimoto, Shun*; Utsunomiya, Takashi*; Yashima, Hiroshi*; Ninomiya, Kazuhiko*; Omoto, Takashi*; Nakagaki, Reiko*; Shima, Tatsushi*; Takahashi, Naruto*; Shinohara, Atsushi*; Kinoshita, Norikazu*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.89 - 93, 2011/02

In this work, we tried to determine reaction cross sections for Y and Tb induced by neutrons at 300 MeV, which have never been reported. The irradiations were carried out using neutrons produced through $$^{7}$$Li(p, n) reaction at N0 beam line in the Research Center for Nuclear Physics (RCNP), Osaka University. To estimate quasi-monoenergetic neutron induced cross sections, the target stacks of Y and Tb were irradiated on the two angles of 0 degree and 30 degree for the axis of the primary proton beam. Neutron cross sections were estimated by subtracting the activities produced in the samples placed on 30 degree from those of 0 degree to correct the contribution of the low energy tail in the neutron spectrum.

Journal Articles

Unique extraction behavior of americium and curium in a system of TBP and calcium nitrate hydrate melt

Okude, Genki*; Fujii, Toshiyuki*; Uehara, Akihiro*; Sekimoto, Shun*; Minato, Kazuo; Yamana, Hajimu*

IOP Conference Series; Materials Science and Engineering, 9, p.012067_1 - 012067_7, 2010/05

 Times Cited Count:2 Percentile:25.97

Oral presentation

Shielding experiments at Fermilab; Calculation analysis for Moyer parameter

Matsuda, Norihiro; Kasugai, Yoshimi; Sakamoto, Yukio; Nakashima, Hiroshi; Matsumura, Hiroshi*; Iwase, Hiroshi*; Toyoda, Akihiro*; Yashima, Hiroshi*; Sekimoto, Shun*; Oishi, Koji*; et al.

no journal, , 

no abstracts in English

Oral presentation

Measurements of prompt fission $$gamma$$-rays from the reaction $$^{235}$$U ($$n_{th},f$$)

Makii, Hiroyuki; Nishio, Katsuhisa; Nishinaka, Ichiro; Hirose, Kentaro; Orlandi, R.; Smallcombe, J.; L$'e$guillon, R.; Sekimoto, Shun*; Takamiya, Koichi*; Otsuki, Tsutomu*

no journal, , 

The Japanese government has a plan to remove the melted reactor fuel for the full deconstruction of Fukushima I Nuclear Power Plants, which have been seriously damaged in the Great East Japan Earthquake. The removal of the fuel must be carried out without reaching the criticality of the fuel. However, it is quite difficult to detect prompt neutrons accompanied by fission to monitor the increased fission rate due to the background $$gamma$$-rays from the fission products in the fuel. On the other hand, the spontaneous fission of $$^{252}$$Cf shows a high energy $$gamma$$-ray component around $$E_{gamma}$$ = 14 MeV, which is significantly larger than that for the background $$gamma$$-rays from the fission products. We are proposing to develop a system based on the use of the high energy $$gamma$$-rays accompanied by fission. In order to design the system, it is essential to know the spectrum of prompt fission $$gamma$$-rays up to more than 8 MeV for thermal neutron-induced fission of $$^{235}$$U. However, no data are available in the energy range larger than 7 MeV. This prompted us to make a new measurement to extend the known prompt $$gamma$$ ray energy spectrum up to 20 MeV. In this contribution, we will present the results of a test experiment to know the measuring condition such as background $$gamma$$-ray yield and spectrum.

Oral presentation

Measurement of high-energy $$gamma$$-rays accompanied by fission for a new detector to monitor subcriticality

Nishio, Katsuhisa; Makii, Hiroyuki; Hirose, Kentaro; Nishinaka, Ichiro; Orlandi, R.; Smallcombe, J.; Otsuki, Tsutomu*; Sekimoto, Shun*; Takamiya, Koichi*

no journal, , 

no abstracts in English

Oral presentation

Measurement of high-energy prompt fission $$gamma$$-rays from neutron induced fission of $$^{235}$$U

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.; Ogawa, Tatsuhiko; Soldner, T.*; Hambsch, F.-J.*; A$"i$che, M.*; Astier, A.*; et al.

no journal, , 

The Japanese government has a plan to remove the fuel debirs for the full deconstruction of Fukushima I Nuclear Power Plants. The fuel debris must be removed without reaching criticality. However, it is difficult to monitor the fission rate due to the background $$gamma$$ rays coming from long-lived fission products. We are proposing to develop a system based on the use of the high-energy prompt fission $$gamma$$ rays, whose energies are high enough to be separated from the background. To design the system, it is essential to know the spectrum of prompt fission $$gamma$$ rays up to more than 7 MeV for $$^{235}$$U($$n, f$$). So far, no data are available in the $$gamma$$-ray energy range larger than 7 MeV. This prompted us to make a new measurement to extend the $$gamma$$-ray spectrum limit to higher energies. The measurement has been carried out at the PF1b cold-neutron beam facility of the Institut Laue-Langevin. In this contribution we will present the results obtained the measurement.

Oral presentation

Measurement of high-energy prompt fission $$gamma$$ rays in $$^{235}$$U(n$$_{th}$$,f)

Ogawa, Tatsuhiko; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.*; Soldner, T.*; Hambsch, F.-J.*; A$"i$che, M.*; Astier, A.*; et al.

no journal, , 

Measurement of $$gamma$$-rays emitted from fission of actinide has been conducted for radiation transport analysis in reactors, safety of spent fuel, and fundamental nuclear physics. In earlier studies, $$gamma$$-rays up to 8 MeV were measured because they are those emitted by fission fragments at excited states. According to some theoretical studies, however, some fission fragments have excitation energy up to 20 MeV and they emit $$gamma$$-rays above 8 MeV. In this study, the $$gamma$$-rays produced by fission of $$^{235}$$U induced by thermal neutrons were measured with LaBr scintillators at the high-flux reactor in the Institut Laue Langevin. The obtained $$gamma$$-ray spectrum agreed with the earlier measurement below 8 MeV, forms a bump above 10 MeV, and smoothly continued up to 20 MeV. The measurement in this study clarified the $$gamma$$-ray energy spectrum attributed to fission reactions up to 20 MeV in case of $$^{235}$$U(n$$_{th}$$,f).

Oral presentation

Measurement of high-energy prompt fission $$gamma$$ rays in $$^{235}$$U(n$$_{th}$$,f)

Ogawa, Tatsuhiko; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.*; Soldner, T.*; Hambsch, F.-J.*; A$"i$che, M.*; Astier, A.*; et al.

no journal, , 

Measurement of $$gamma$$-rays emitted from fission of actinide has been conducted for radiation transport analysis in reactors, safety of spent fuel, and fundamental nuclear physics. In earlier studies, $$gamma$$-rays up to 8 MeV were measured because they are those emitted by fission fragments at excited states. According to some theoretical studies, however, some fission fragments have excitation energy up to 20 MeV and they emit $$gamma$$-rays above 8 MeV. In this study, the $$gamma$$-rays produced by fission of $$^{235}$$U induced by thermal neutrons were measured with LaBr scintillators at the high-flux reactor in the Institut Laue Langevin. The obtained $$gamma$$-ray spectrum agreed with the earlier measurement below 8 MeV, forms a bump above 10 MeV, and smoothly continued up to 20 MeV. The measurement in this study clarified the $$gamma$$-ray energy spectrum attributed to fission reactions up to 20 MeV in case of $$^{235}$$U(n$$_{th}$$,f).

Oral presentation

Measurement of high-energy prompt fission $$gamma$$-ray emission in $$^{235}$$U ($$n_{rm th},f$$)

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.*; Ogawa, Tatsuhiko; Soldner, T.*; K$"o$ster, U.*; Hambsch, F.-J.*; Kawano, Toshihiko*; et al.

no journal, , 

Oral presentation

Measurement of high-energy prompt fission gamma-rays for $$^{235}$$U(n$$_{rm th}$$,f)

Nishio, Katsuhisa; Makii, Hiroyuki; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.*; Ogawa, Tatsuhiko; Soldner, T.*; K$"o$ster, U.*; Pollitt, A.*; Hambsch, F.-J.*; et al.

no journal, , 

no abstracts in English

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