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Journal Articles

Activation measurement for thermal-neutron capture cross-section of Cesium-135

Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*

KURNS Progress Report 2018, P. 106, 2019/08

Under the ImPACT project, the neutron capture cross-section measurements of Cesium-135 ($$^{135}$$Cs) among the long-lived fission products have been performed at Kyoto University. This paper reports measurements of the thermal-neutron capture cross-section of $$^{135}$$Cs at the Kyoto University Research Reactor (KUR).

Journal Articles

Measurements of the $$^{243}$$Am neutron capture and total cross sections with ANNRI at J-PARC

Kimura, Atsushi; Nakamura, Shoji; Terada, Kazushi*; Nakao, Taro*; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.

Journal of Nuclear Science and Technology, 56(6), p.479 - 492, 2019/06

Journal Articles

International Conference on Nuclear Data for Science and Technology (ND2019), 3; Evaluation and theory

Nakayama, Shinsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Hashimoto, Shintaro

Kaku Deta Nyusu (Internet), (123), p.53 - 59, 2019/06

The 2019 International Conference on Nuclear Data for Science and Technology (ND2019) was held at the China National Convention Center on May 19-24, 2019. The series of the ND conferences are the largest conferences in nuclear data research field that are held every three years. In this paper, as a part of the conference reports of ND2019, the authors gave summaries of the presentations on nuclear data evaluation and theory conducted at the conference.

Journal Articles

Phenomenological level density model with hybrid parameterization of deformed and spherical state densities

Furutachi, Naoya*; Minato, Futoshi; Iwamoto, Osamu

Journal of Nuclear Science and Technology, 56(5), p.412 - 424, 2019/05

A phenomenological level density model that has different level density parameter sets for the state densities of the spherical and the deformed states, and the optimization of the parameters using the experimental data of the average s-wave neutron resonance spacing are presented. The transition to the spherical state from the deformed one is described using the parameters derived from a microscopic nuclear structure calculation. The nuclear reaction calculation has been performed by the statistical model using the present level density. Resulting cross sections for various reactions with the spherical, deformed and transitional target nuclei shows a fair agreement with the experimental data, which indicates the effectiveness of the present model. The role of the rotational collective enhancement in the calculations of those cross sections is also discussed.

Journal Articles

Measurements of neutron capture reaction cross-sections at ANNRI of MLF in J-PARC

Iwamoto, Osamu

ImPACT Fujita Puroguramu Kokai Seika Hokokukai "Kaku Henkan Niyoru Koreberu Hoshasei Haikibutsu No Ohaba Na Teigen, Shigenka" Seika Hokokusho, Shiryoshu, p.78 - 81, 2019/03

Measurements of Neutron Capture Reaction Cross-Sections at ANNRI of MLF in J-PARC have been conducted as a part of the ImPACT Fujita Program titled "Reduction and Resource Recycling of High-level Radioactive Wastes through Nuclear Transmutation". A resonance cross section of the neutron capture reaction with Cs-135 was measured. In addition, a thermal cross section and a resonance integral have been deduced by an activation experiment at KUR. Summary of this study will be reported.

Journal Articles

Development of the standard evaluated database of nuclear reactions for long lived fission products

Iwamoto, Osamu

ImPACT Fujita Puroguramu Kokai Seika Hokokukai "Kaku Henkan Niyoru Koreberu Hoshasei Haikibutsu No Ohaba Na Teigen, Shigenka" Seika Hokokusho, Shiryoshu, p.102 - 105, 2019/03

Study on the development of the standard evaluated database of nuclear reactions for long lived fission products has been conducted as a part of the ImPACT Fujita Program titled "Reduction and Resource Recycling of High-level Radioactive Wastes through Nuclear Transmutation". The database of the neutron and proton induced reactions on LLFPs and their neighbor nuclei has been developed taking account of the up-to-date theoretical and experimental knowledges. In addition, the update of the calculation methods of deuteron induced reactions has also conducted. Summary of this study will be reported.

Journal Articles

Impulsing paradigm change through disruptive technologies program, ImPACT; Reduction and resource recycling of high-level radioactive waste through nuclear transmutation

Iwamoto, Osamu; Fujita, Reiko*; Niita, Koji*; Watanabe, Yukinobu*

Kaku Deta Nyusu (Internet), (122), p.33 - 43, 2019/02

A program related to the transmutation of long-lived fission products (LLFPs) entitled "Reduction and Resource Recycling of High-level Radioactive Wastes through Nuclear Transmutation" has been conducted under the Impulsing Paradigm Change through Disruptive Technologies Program (ImPACT) organized by the Cabinet Office since 2014 and it will be finished in FY 2018. Various activities from acquisition of basic data to examination of transmutation scenario are being carried out as the five separated projects. R&Ds related to nuclear data are also conducted and many outcomes are being produced. This article describes results of the two projects related nuclear data with a short introduction of the whole project.

Journal Articles

Measurements of gamma-ray emission probabilities in the decay of americium-244g

Nakamura, Shoji; Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Iwamoto, Osamu; Harada, Hideo; Uehara, Akihiro*; Takamiya, Koichi*; Fujii, Toshiyuki*

Journal of Nuclear Science and Technology, 56(1), p.123 - 129, 2019/01

 Percentile:100(Nuclear Science & Technology)

Accurate data of $$gamma$$-ray emission probabilities are frequently needed when one quantitatively determines the amount of isotope by $$gamma$$-ray measurements or obtains neutron capture cross-sections using them. Americium-243, one of the most important minor actinides, produces $$^{244}$$Am after neutron capture. The 744-keV $$gamma$$-ray decaying from the ground state of $$^{244}$$Am has a relatively large $$gamma$$-ray emission probability c.a. 66%, however, its uncertainty is as large as 29%. The uncertainty of the $$gamma$$-ray emission probability leads to a major factor of the systematic uncertainty on determining an amount of isotope, and therefore the $$gamma$$-ray emission probability was measured by using an activation method and an examined level structure of $$^{244}$$Cm. In this study, the emission probability of 744-keV $$gamma$$ ray was derived as 66.5$$pm$$1.1%, and its uncertainty was improved from 29% to 2%.

JAEA Reports

Proceedings of the 2017 Symposium on Nuclear Data; November 16-17, 2017, iVil, Tokai-mura, Ibaraki, Japan

Nishio, Katsuhisa; Utsuno, Yutaka; Chiba, Satoshi*; Koura, Hiroyuki; Iwamoto, Osamu; Nakamura, Shoji

JAEA-Conf 2018-001, 226 Pages, 2018/12

JAEA-Conf-2018-001.pdf:22.81MB

The 2017 Symposium on Nuclear Data was held at iVil in Tokai on November 16-17, 2017. The symposium was hosted by the Nuclear Data Division of the Atomic Energy Society of Japan (AESJ) and Advanced Science Research Center of Japan Atomic Energy Agency, and co-hosted by Japanese Nuclear Data Committee of AESJ and North Kanto Branch of AESJ. In the symposium, a tutorial was given by Prof. Rykaczewski (ORNL) "New nuclear data from total absorption spectroscopy and beta-delayed neutron measurements", as well as six oral sessions, "Nuclear Physics and Nuclear Data" (two sessions), "Nuclear Theory and Nuclear Data", "Reactors" and "Nuclear Data and Their Applications" (two sessions). In addition, recent advances in experiment, theory, evaluation, benchmark, and application were presented in the poster session. The symposium had 79 participants, who contributed to very active and fruitful discussions. This report consists of 37 papers, including those of 14 oral and 23 poster presentations.

Journal Articles

Present status and future plan of JENDL

Iwamoto, Osamu

JAEA-Conf 2018-001, p.87 - 91, 2018/12

Status and plan of JENDL will be presented. After the release of JENDL-4.0 in 2010, six special purpose files have been developed. Four of them were already released and two are under preparation for the release. New decay and yield data for fission products were released as JENDL/FPD-2011 and JENDL/FPY-2011 in 2011, respectively. JENDL-4.0/HE released in 2015 includes proton and neutron induced reaction data up to 200 MeV. Comprehensive decay data were released as JENDL/DDF-2015 which contains data for 3,237 nuclides. New photonuclear reaction data JENDL/PD-2016 and an activation file JENDL/AD-2017 are under preparation for release. Regarding general purpose file, two activities are in progress. One is JENL-4.0u which is created for maintenance of JENDL-4.0 and the other is development of next version of JENDL. For the next JENDL, evaluation for light nuclei and structure material are in progress. It is planed that next version of JENDL will be JENDL-5 which contains nuclear data for all nuclei having natural abundance. Addition of covariance data will be one of the main targets.

Journal Articles

Progress of neutron-capture cross-section measurements promoted by ImPACT project at ANNRI in MLF of J-PARC

Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*

JAEA-Conf 2018-001, p.199 - 203, 2018/12

Study on cross-section measurements has been promoted for $$^{135}$$Cs among long-lived fission products in ImPACT Project. The feasibility study on $$^{79}$$Se sample preparation also has been conducted to measure its cross sections in future. During the feasibility study, we started the neutron-capture cross-section measurements of stable Se isotopes. This paper reports research progresses on preparation of a radioactive $$^{135}$$Cs sample, neutron irradiation experiments with the Cs sample, and cross-section measurements of stable Se isotopes.

Journal Articles

Analysis of $$^{135}$$Cs/$$^{137}$$Cs isotopic ratio for samples used for neutron capture cross section measurement project by thermal ionization mass spectrometry

Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*; Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu

JAEA-Conf 2018-001, p.205 - 210, 2018/12

In the ImPACT project, high-precision mass analysis was performed on a $$^{137}$$Cs standard solution for using $$^{135}$$Cs included in the standard solution as an impurity to measure the $$^{135}$$Cs cross-sections. A $$^{137}$$Cs standard solution of only 10Bq (pg order) was analyzed, and the isotope ratio of $$^{135}$$Cs and $$^{137}$$Cs was obtained with an accuracy of 0.5%.

Journal Articles

Measurements of neutron total and capture cross sections of $$^{241}$$Am with ANNRI at J-PARC

Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Nakamura, Shoji; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.

Journal of Nuclear Science and Technology, 55(10), p.1198 - 1211, 2018/10

 Times Cited Count:1 Percentile:38.14(Nuclear Science & Technology)

Journal Articles

Role of breakup processes in deuteron-induced spallation reactions at 100-200 MeV/nucleon

Nakayama, Shinsuke; Furutachi, Naoya; Iwamoto, Osamu; Watanabe, Yukinobu*

Physical Review C, 98(4), p.044606_1 - 044606_8, 2018/10

 Times Cited Count:1 Percentile:49.68(Physics, Nuclear)

Use of deuteron-induced spallation reactions at intermediate energies has recently been proposed for transmutation of several long-lived fission products (LLFPs). In the design study of a transmutation system using a deuteron primary beam, accurate cross section data of deuteron-induced reactions on the LLFPs are indispensable. In the present study, production cross sections of residual nuclei in the deuteron-induced reactions on $$^{93}$$Zr and $$^{107}$$Pd at $$100-200$$ MeV/nucleon are analyzed using DEURACS, in which the breakup processes are explicitly taken into account. The calculated values reproduced the experimental data quantitatively well. From a component-by-component analysis, it was found that the components of nucleon absorption make the significant contributions to residual nuclei production. This result strongly indicates that consideration of the breakup processes is essentially important to predict production of residual nuclei in deuteron-induced reactions.

Journal Articles

2018 Annual Meeting of Japan Atomic Energy Society, Session of Subcommittees and Liaison Meetings, Nuclear Subcommittee [co-sponsor of Sigma Advisory Committee], Present status and future of nuclear data evaluation code in Japan, 2; Progress of a nuclear model code CCONE

Iwamoto, Osamu

Kaku Deta Nyusu (Internet), (120), p.11 - 18, 2018/06

Progress of the nuclear reaction model code CCONE is shown based on the presentation at the session titled "Present status and future of nuclear data evaluation code in Japan" at the session of Nuclear Data subcommittee at 2018 Annual Meeting of Japan Atomic Energy Society. The CCONE code is developed for the nuclear data evaluation calculation for JENDL. It was applied to the nuclear data evaluation for actinides at first, and extension for the higher energies reactions was performed. At present it is applied to various data evaluations such as photonuclear reaction and decay data.

Journal Articles

Report on the 30th Meeting of Working Party on International Nuclear Data Evaluation Co-operation

Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Yokoyama, Kenji; Tada, Kenichi

Kaku Deta Nyusu (Internet), (120), p.35 - 46, 2018/06

We report 30th WPEC meeting, expert group meeting, and subgroup meeting in Paris, May 14-18, 2018.

Journal Articles

Cutting-edge studies on nuclear data for continuous and emerging need, 8; Evolution of the nuclear data library JENDL

Iwamoto, Osamu; Shibata, Keiichi; Iwamoto, Nobuyuki; Chiba, Go*

Nippon Genshiryoku Gakkai-Shi, 60(6), p.357 - 361, 2018/06

Nuclear data library consists of the results of related studies on nuclear data. Nuclear data can show worth through utilization of the nuclear data library which is the outcome of the nuclear data study. As the last lecture over 8 serial ones, the Japanese nuclear data library JENDL is explained. Sections of "General purpose file and its history", "recent progress of special purpose file", and "international status of nuclear data library" are introduced and one of "prospect of JENDL and nuclear data study" is shown.

Journal Articles

CIELO collaboration summary results; International evaluations of neutron reactions on uranium, plutonium, iron, oxygen and hydrogen

Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Kahler, A. C.*; Talou, P.*; Plompen, A. J.*; Schillebeeckx, P.*; et al.

Nuclear Data Sheets, 148, p.189 - 213, 2018/02

 Times Cited Count:8 Percentile:4(Physics, Nuclear)

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear facilities - $$^{235}$$U, $$^{238}$$U, $$^{239}$$Pu, $$^{56}$$Fe, $$^{16}$$O and $$^{1}$$H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality. This report summarizes our results and outlines plans for the next phase of this collaboration.

Journal Articles

Theoretical model analysis of $$(d,xn)$$ reactions on $$^7$$Li at 25, 40, and 102 MeV

Sadamatsu, Hiroki*; Nakayama, Shinsuke; Watanabe, Yukinobu*; Iwamoto, Osamu; Ogata, Kazuyuki*

JAEA-Conf 2017-001, p.135 - 140, 2018/01

In recent years, the demand for intense neutron sources has been increasing in various applications such as nuclear transmutation of high-level radioactive waste and medical radioisotopes production. Deuteron accelerator-based neutron sources are promised as one of the candidates. Therefore, we have developed a code system dedicated for the deuteron-induced reactions, called DEURACS. In the present work, we focus on deuteron-induced neutron production from $$^7$$Li target. The calculated double differential cross sections for $$(d,xn)$$ reactions at incident energies of 25, 40, and 102 MeV are compared with the measured ones, and the applicability of DEURACS is discussed.

Journal Articles

Theoretical model analysis of composite-particle emission from deuteron-induced reactions

Nakayama, Shinsuke; Iwamoto, Osamu; Watanabe, Yukinobu*

JAEA-Conf 2017-001, p.91 - 96, 2018/01

Toward evaluation of deuteron nuclear data, we have been developing a code system dedicated for the deuteron-induced reactions, called DEURACS. In the present work, we make an improvement in DEURACS and apply it to composite-particle emission from deuteron-induced reactions. The calculation using DEURACS reproduces the experimental double-differential cross sections of $$(d,xd)$$, $$(d,xt)$$, $$(d,x^3 {rm He})$$, and $$(d,xalpha)$$ reactions on $$^{27}$$Al and $$^{58}$$Ni at incident energy of 80 MeV quantitatively well. From the results of the analyses, it is shown that the treatment of inelastic scattering and pick-up reaction processes is important in the calculation of deuteron-induced composite-particle emission.

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