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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%.

Journal Articles

Simultaneous measurement of neutron-induced fission and capture cross sections for $$^{241}$$Am at neutron energies below fission threshold

Hirose, Kentaro; Nishio, Katsuhisa; Makii, Hiroyuki; Nishinaka, Ichiro*; Ota, Shuya*; Nagayama, Tatsuro*; Tamura, Nobuyuki*; Goto, Shinichi*; Andreyev, A.; Vermeulen, M. J.; et al.

Nuclear Instruments and Methods in Physics Research A, 856, p.133 - 138, 2017/06

 Times Cited Count:3 Percentile:27.27(Instruments & Instrumentation)

Journal Articles

Journal Articles

Search for neutron resonances of $$^{106}$$Pd

Nakamura, Shoji; Kimura, Atsushi; Toh, Yosuke; Harada, Hideo; Katabuchi, Tatsuya*; Mizumoto, Motoharu*; Igashira, Masayuki*; Hori, Junichi*; Kino, Koichi*

JAEA-Conf 2015-003, p.113 - 118, 2016/03

Experiments were carried out with the Ge detector of ANNRI to confirm whether or not the weak resonances were surely due to $$^{106}$$Pd. The prompt $$gamma$$ rays due to capture reaction of $$^{106}$$Pd were clearly observed at the $$gamma$$-ray energy at 115 kev and around 300 keV. When a TOF spectrum was extracted by gating at the prompt $$gamma$$ ray around 300 keV, the small resonance peaks were revealed at the neutron energy of 146 and 156 eV.

Journal Articles

Current activities and future plans for nuclear data measurements at J-PARC

Kimura, Atsushi; Harada, Hideo; Nakamura, Shoji; Iwamoto, Osamu; Toh, Yosuke; Koizumi, Mitsuo; Kitatani, Fumito; Furutaka, Kazuyoshi; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.

European Physical Journal A, 51(12), p.180_1 - 180_8, 2015/12

 Percentile:100(Physics, Nuclear)

Journal Articles

Neutron capture cross section and capture $$gamma$$-ray spectra of $$^{138}$$Ba in the keV-neutron energy region

Katabuchi, Tatsuya*; Yanagida, Shotaro*; Terada, Kazushi; Iwamoto, Nobuyuki; Igashira, Masayuki*

EPJ Web of Conferences (Internet), 93, p.02008_1 - 02008_2, 2015/05

 Percentile:100

$$^{138}$$Ba has the smallest neutron capture cross section among the stable Ba isotopes. The neutron capture reaction of $$^{138}$$Ba is dominated by resolved resonances in the astrophysically relevant energy region. Thus, reliable experimental data of the capture cross section are necessary. In the present work, we measured the neutron capture cross section of $$^{138}$$Ba in the energy region from 15 to 100 keV by the time-of-flight method at the Tokyo Institute of Technology. The capture cross sections were obtained from the pulse height spectra by the pulse-height weighting technique. A comparison of the present results with previous experimental data and evaluated data was made. We also derived $$gamma$$-ray spectra by unfolding the pulse height spectra. It was revealed that the shape of $$gamma$$-ray spectra strongly depends on neutron energy.

Journal Articles

Research and development for accuracy improvement of neutron nuclear data on minor actinides

Harada, Hideo

Kaku Deta Nyusu (Internet), (109), p.44 - 47, 2014/10

Improvement of accuracy of neutron nuclear data for minor actinides (MAs) and long-lived fission products (LLFPs) is required for developing innovative nuclear system transmuting these nuclei. In order to meet the requirement, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program". The AIMAC project team is composed of researchers in four different fields: differential nuclear data measurement, integral nuclear data measurement, nuclear chemistry, and nuclear data evaluation. By integrating all of the forefront knowledge and techniques in these fields, the research project team aims at improving the accuracy of the data. The background, goal and brief research plan of the AIMAC project are explained.

Journal Articles

Maxwellian-averaged neutron-induced reaction cross sections and astrophysical reaction rates for $$kT$$ = 1 keV to 1 MeV calculated from microscopic neutron cross section library JENDL-3.3

Nakagawa, Tsuneo; Chiba, Satoshi; Hayakawa, Takehito; Kajino, Toshitaka*

Atomic Data and Nuclear Data Tables, 91(2), p.77 - 186, 2005/11

 Times Cited Count:20 Percentile:19.94(Physics, Atomic, Molecular & Chemical)

no abstracts in English

Journal Articles

Simulation of 4$$pi$$ Ge spectrometer by Geant4

Goto, Jun; Sugawara, Masahiko*; Oshima, Masumi; Toh, Yosuke; Kimura, Atsushi; Osa, Akihiko; Koizumi, Mitsuo; Mizumoto, Motoharu; Osaki, Toshiro*; Igashira, Masayuki*; et al.

AIP Conference Proceedings 769, p.788 - 791, 2005/05

no abstracts in English

Journal Articles

$$s$$-process branching at $$^{185}$$W revised

Mohr, P.*; Shizuma, Toshiyuki; Ueda, Hiroyasu*; Goko, Shinji*; Makinaga, Ayano*; Hara, Kaoru*; Hayakawa, Takehito; Lui, Y.-W.*; Ogaki, Hideaki*; Utsunomiya, Hiroaki*

Physical Review C, 69(3), p.032801_1 - 032801_4, 2004/03

 Times Cited Count:28 Percentile:16.68(Physics, Nuclear)

The neutron capture cross section of the unstable s-process branching nucleus $$^{185}$$W has been derived from experimental data of the inverse $$^{186}$$W($$gamma$$,n)$$^{185}$$W photodisintegration taken with monochromatic photon beams from laser Compton scattering. The result of $$sigma = 553 pm 60$$mb at $$kT = 30$$keV leads to a relatively high effective neutron density in the classical s process of $$N_{rm{n}} = 4.7 times 10^8,{rm{cm}}^{-3}$$. A realistic model for the s process in thermally pulsing AGB stars overestimates the abundance of $$^{186}$$Os significantly because of the relatively small neutron capture cross section of $$^{185}$$W.

Journal Articles

Neutron capture cross section to $$^{186}$$Re isomeric state

Hayakawa, Takehito; Shizuma, Toshiyuki; Yamauchi, Toshihiko; Minehara, Eisuke; Arisawa, Takashi

Nuclear Physics A, 718, p.665c - 667c, 2003/05

no abstracts in English

JAEA Reports

Nuclear reactions in ultra-magnetized supernovae

Kondratyev, V. N.

JAERI-Research 2002-010, 32 Pages, 2002/06

JAERI-Research-2002-010.pdf:2.09MB

no abstracts in English

Journal Articles

Chemical analysis of transuranium nuclides in the uranium solution of the JCO criticality accident

Shinohara, Nobuo; Kono, Nobuaki; Suyama, Kenya; Inagawa, Jun; Nakahara, Yoshinori; Kurosawa, Setsumi; Watanabe, Kazuo; Usuda, Shigekazu; Oshima, Masumi; Katsuta, Hiroji; et al.

Radiochimica Acta, 89(3), p.135 - 138, 2001/05

 Times Cited Count:2 Percentile:77.58(Chemistry, Inorganic & Nuclear)

no abstracts in English

JAEA Reports

Preliminary experiment of neutron capture cross section of Tc-99 with lead slowing-down spectrometer

*

JNC-TJ9400 2000-009, 63 Pages, 2000/02

JNC-TJ9400-2000-009.pdf:2.48MB

The present status of nuclear data for technetium (Tc)-99, which is a well-known fission product (FP), has been reviewed and investigated. And making use of the Kyoto university Lead Slowing-down Spectrometer (KULS), the cross section of the $$^{99}$$Tc (n, $$gamma$$) $$^{100}$$Tc reaction has been measured in the energy range from thermal to keV neutron energy with an Ar-gas proportinal counter. The neutron flux/spectrum has been monitored with a BF$$_{3}$$ proportional counter, and the relative measurement has been normalized to the well-known standard capture cross section value for the $$^{99}$$Tc (n, $$gamma$$) $$^{100}$$Tc reaction at 0.0253 eV. Self-shielding corrections, especially near the resonance peaks, were made by the calculations with the MCNP code. Although the experimental data measured by Chou et al with a lead slowing-down spectrometer are higher in general, the energy dependency is similar to the present measurement. The evaluated data in ENDF/B-VI and JENDL-3.2 are higher near the resonances at 5.6 and 20 eV and above several 100 eV. A lead slowing-down spectrometer was installed coupled to a 46 MeV electron linac at the Research Reactor Institute, Kyoto university (KURRI). Characteristics of the Kyoto University Lead Slowing-down Spectrometer (KULS) were measured and (1)the relation between neutron slowing-down time t($$mu$$s) and energy E(keV) (E=190/t$$^{2}$$ in Bi hole and E=156/t$$^{2}$$ in Pb hole) and (2)the energy resolution ($$sim$$40% in Bi and Pb holes) were experimentally investigated. (3)The neutron energy spectrum in the KULS was also measured by the neutron TOF method. The results obtained by the MCNP code were in general agreement with these experimental ones.

JAEA Reports

Measurement of neutron capture cross sections of Tc-99

*

JNC-TJ9400 2000-008, 61 Pages, 2000/02

JNC-TJ9400-2000-008.pdf:2.5MB

For studies on nuclear transmutation of long-lived fission products (LLFPs) in a fast reactor, detailed characteristics of reactor core such as transmutation performance have to be investigated, so accurate neutron cross section data of LLFPs become necessary. Therefore, the keV-neutron capture cross sections of Tc-99, which is one of important LLFPs, were measured in the present study to obtain the accurate data. The measurement was relative to the standard capture cross sections of Au-197. A neutron time-of-flight method was adopted with a ns-pulsed neutron source by a Pelletron accelerator and a large anti-Compton NaI(TI) gamma-ray detector. As a result, the capture cross sections of Tc-99 were obtained with the error of about 5 % in the incident neutlon energy region of 10 to 600 keV. The present data were compared with other experimental data and the evaluated values of JENDL-3.2, and it was found that the evaluations of JENDL-3.2 were 15-20 % smaller than the present measurements.

JAEA Reports

Improvement of covariance data for fast reactors

*; *

JNC-TJ9400 2000-004, 109 Pages, 2000/02

JNC-TJ9400-2000-004.pdf:4.96MB

We estimated covariances of the JENDL-3.2 data on the nuclides and reactions needed to analyze fast-reactor cores for the past three years, and produced covariance files. The present work was undertaken to re-examine the covariance files and to make some improvements. The covariances improved are the ones for the inelastic scattering cross section of $$^{16}$$O, the total cross section of $$^{23}$$Na, the fission cross section of $$^{235}$$U, the capture cross section of $$^{238}$$U, and the resolved resonance parameters for $$^{238}$$U. Moreover, the covariances of $$^{233}$$U data were newly estimated by the present work. The covariances obtained were compiled in the ENDF-6 format.

JAEA Reports

Maxwellian-averaged cross sections calculated from JENDL-3.2

Nakagawa, Tsuneo; Chiba, Satoshi; Osaki, Toshiro*; Igashira, Masayuki*

JAERI-Research 2000-002, p.93 - 0, 2000/02

JAERI-Research-2000-002.pdf:4.41MB

no abstracts in English

JAEA Reports

Analysis of the Rossendorf SEG experiments using the JNC route for reactor calculation

Dietze, K.

JNC-TN9400 99-089, 20 Pages, 1999/11

JNC-TN9400-99-089.pdf:0.66MB

The integral experiments performed at the Rossendorf fast-thermal coupled reactor RRR/SEG have been reanalyzed using the JNC route for reactor calculation JENDL3.2/SLAROM / CITATION / JOINT / PERKY. The Rossendorf experiments comprise sample reactivity measurements with pure fission products and structural material in five configurations with different neutron and adjoint spectra. The shapes of the adjoint spectra have been designed to get high sensitivities to neutron capture or the scattering effect. The calculated neutron and adjoint spectra are in good agreement with former results obtained with the European route JEF2.2/ECCO/ERANOS. The C/E-values of the central reactivity worths of samples under investigation are given. Deviations in the results of both routes are due to the different libraries, codes, and self-shielding treatments used in the calculations. Results outside of the error are discussed.

JAEA Reports

Measurement of neutron capture cross sections of Tc-99

*

JNC-TJ9400 99-001, 78 Pages, 1999/03

JNC-TJ9400-99-001.pdf:2.07MB

For studies on incineration of long-lived fission products (LLFPs) in a fast reactor, detailed characteristics of reactor core such as incineration performance have to be investigated. Therefore, accurate neutron cross section data of LLFPs become necessary. In the present study, in order to perform the precise measurements of keV-neutron capture cross sections of Tc-99, which is one of most important LLFPs, the details of the Tc-99 sample and the measurements with our experimental facilities were investigated.

Journal Articles

Measurement of fission product yields from neutron-induced fission of americium-241

Shinohara, Nobuo; Hatsukawa, Yuichi; ; Kono, Nobuaki

Journal of Nuclear Science and Technology, 36(3), p.232 - 241, 1999/03

 Times Cited Count:2 Percentile:76.23(Nuclear Science & Technology)

no abstracts in English

72 (Records 1-20 displayed on this page)