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Journal Articles

Systematics and uncertainties of Hamiltonian parameters of soft-rotator model for actinides and their implications for nuclear data calculations

Chiba, Satoshi; Koura, Hiroyuki; Maruyama, Toshiki; Kunieda, Satoshi; Soukhovitskij, E. Sh.*

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.305 - 308, 2008/06

 Times Cited Count:0 Percentile:100

A coupled-channel (CC) method based on the soft-rotator model (SRM) wave functions, SRM-CC, has been recognized as a powerful tool to calculate, estimate and evaluate the nucleon-induced cross sections. It is because that this method can take account of the information from the nuclear structure and reaction studies simultaneously. For example, the coupling strengths required in the coupled-channel calculation is determined from analyses of low-lying collective level structure of target nuclei. However, nobody has looked into so far how the uncertainties of the SRM parameters affects the calculated cross section data. In this work, collective level structure of 19 even-even actinide nuclei are analyzed in terms of the soft-rotator model (SRM). Hamiltonian parameters of SRM to describe the low-lying level scheme and their uncertainties are obtained. Systematic trends are found for major Hamiltonian parameters as a function of ground-state quadrupole deformation which are important to estimate low-lying level structure of other e-e nuclei for which level structure is unknown or only partly known. Then, those parameters and their uncertainties are used to calculate neutron cross sections and their covariance of actinides in terms of SRM-CC. Furthermore, effects of side-band coupling is investigated. Especially, effects of coupling are noticeable for low-energy observables, e.g., strength functions. Such saturated calculations are not possible in RRM (rigid rotor model)-CC approach, making SRM-CC an effective method for investigations of reaction mechanisms and nuclear data evaluation.

Journal Articles

Accelerator-based facility design in association with nuclear data

Takada, Hiroshi

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.23 - 28, 2008/05

In the design study of a large accelerator facility using high energy and high intensity beam accelerator as examples of J-PARC and SNS, it is required to seek the best neutronic performance and assure engineering feasibilities such as heat removal from the target and its surroundings, capability on installation and assembling, material selection to have enough life-time under radiation environment for reasonable operation duration. It is also important to design sophisticated maintenance scheme to treat highly activated components, and optimal radiation shield around accelerator components and secondary beam lines. High energy nuclear data file and accumulation of new experimental data are indispensable to improve or to know the prediction accuracy of neutronics design by a computer simulation using a model independent of the nuclear data. In this paper, roles of nuclear data in design of accelerator facilities is presented.

Journal Articles

Problem on unresolved resonance data in recent nuclear data libraries

Konno, Chikara; Nakagawa, Tsuneo; Ochiai, Kentaro; Sato, Satoshi; Yamauchi, Michinori

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.713 - 716, 2008/05

A leakage neutron spectrum from a niobium sphere of 0.5 m in radius with a 20 MeV neutron in the center, which was calculated with ANISN, MCNP and JENDL-3.3, had a large strange bump around 100 keV, which originated from the unresolved resonance data. We checked cross section data of (n,$$gamma$$) reaction and elastic scattering in $$^{93}$$Nb with and without self-shielding correction by using a multigroup library of JENDL-3.3. The self-shielding correction of the unresolved resonances seems to be too large even around the upper energy of the unresolved resonance region. It is considered that the average reduced neutron widths or the upper energy of the unresolved resonance region in $$^{93}$$Nb have any problems. It is found out that many nuclei with unresolved resonance data in JENDL-3.3 and ENDF/B-VI have the similar problem. The unresolved resonance data in JENDL-3.3 and ENDF/B-VI should be revised by considering self-shielding correction in the next version.

Journal Articles

Experimental study on breakup reaction of beryllium and carbon induced with 14-MeV neutrons based on emitted charged-particle measurements

Kondo, Keitaro; Murata, Isao*; Ochiai, Kentaro; Miyamaru, Hiroyuki*; Kubota, Naoyoshi*; Konno, Chikara; Nishitani, Takeo

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.407 - 410, 2008/05

Beryllium and carbon are candidate materials of fusion reactors and the $$^{9}$$Be(n,2n+2$$alpha$$) and $$^{12}$$C(n,n'+3$$alpha$$) reactions are important from engineering requirements. In order to estimate double-differential cross sections (DDX) for emitted particles, we have to accurately grasp details of the reaction mechanism. Understanding of the reaction mechanism is also interesting from a viewpoint of nuclear physics. Recently we developed a new spectrometry system with a pencil-beam DT neutron source. Using the system, we carried out detailed measurements of DDX for $$alpha$$-particles emitted from beryllium and carbon. The reaction mechanism was investigated by a Monte Carlo calculation of DDX. For the $$^{9}$$Be(n,2n+2$$alpha$$) reaction, the result suggests importance of the contribution from the $$^{9}$$Be(n,$$alpha$$)$$^{6}$$He*(Ex$$geq$$1.8MeV) reaction. For the $$^{12}$$C(n,n'+3$$alpha$$) reaction, the contribution from the $$^{12}$$C(n,$$alpha$$)$$^{9}$$Be*(Ex$$geq$$2.43MeV) reaction was appeared and its ratio was investigated to explain the shape of DDX for neutrons in lower energy.

Journal Articles

Systematical nucleon-induced optical model analysis for medium and heavy nuclei with coupled-channel framework

Kunieda, Satoshi; Chiba, Satoshi; Shibata, Keiichi; Ichihara, Akira; Sukhovitskij, E.*

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.227 - 230, 2008/05

The optical model analyses were carried out for nucleon-induced reactions on medium and heavy nuclei from 1 keV to 200 MeV. The coupled-channels method based on the rigid-rotator model was employed as an initial approach. It was found that the coupled-channels analyses were indispensable to obtain a global formulation of optical potential. In addition to this, the coupled-channels calculations based on the soft-rotator model was applied to analyses for various even-even fission product isotopes. They reproduced measured cross sections better than the rigid-rotator model in many cases. Though the latter is our ongoing study, we show the advantage of coupled-channels calculations and the applicability of the soft-rotator model in this conference.

Journal Articles

Measurement of total $$gamma$$ absorption for high energy $$gamma$$ rays

Kitatani, Fumito; Harada, Hideo; Hara, Kaoru; Utsunomiya, Hiroaki*; Goko, Shinji*; Kaihori, Takeshi*; Toyokawa, Hiroyuki*

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.123 - 126, 2008/05

Total $$gamma$$ absorption cross sections are most important data used in various fields related to the application of $$gamma$$ rays. However, the measurements of the total $$gamma$$ absorption cross section were difficult for high energy $$gamma$$ rays since there were no suitable $$gamma$$ ray sources. Recently, the nuclear photo-absorption measurement system using the laser-Compton backscattering (LCS) $$gamma$$ rays and the high-resolution high-energy photon spectrometer (HHS) were developed. We have utilized the system to measure the total $$gamma$$ absorption cross section, that is, the sum of the atomic and nuclear interactions. The total $$gamma$$ absorption cross sections at 10 MeV for Al and Cu have been measured with the system. The preliminary results show that the obtained values agree fairly with the theoretical.

Journal Articles

High resolution spectroscopy of the giant resonance in the $$^{16}$$O($$gamma$$,abs) reaction

Harada, Hideo; Kitatani, Fumito; Hara, Kaoru; Utsunomiya, Hiroaki*; Goko, Shinji*; Kaihori, Takeshi*; Toyokawa, Hiroyuki*

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.499 - 502, 2008/05

The characteristics of the nuclear photo-absorption spectroscopy using the laser Compton scattering (LCS) photons and the high-resolution high-energy photon spectrometer (HHS) are presented in this paper. The maximum energy of a LCS photon was increased up to 30 MeV, and the response functions of the HHS were improved. By taking advantage of these achievements, the $$^{16}$$O($$gamma$$,abs) cross section was measured in the giant resonance region, that is, 20 to 25 MeV. The preliminary result with the energy resolution of about 0.1% is presented and compared with the preceding data.

Journal Articles

Performance of a 4$$pi$$ Ge spectrometer for neutron capture cross section measurements

Oshima, Masumi; Hori, Junichi*; Harada, Hideo; Furutaka, Kazuyoshi; Koizumi, Mitsuo; Kitatani, Fumito; Toh, Yosuke; Kimura, Atsushi; Nakamura, Shoji; Igashira, Masayuki; et al.

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.603 - 606, 2008/05

Neutron capture cross sections of minor actinides and long-lived fission products are important for the R&D of innovative nuclear reactors. However, those data are rather poor both in quality and in quantity at present. Thus, we have started projects for neutron cross section measurements. We will construct an innovative $$gamma$$-ray spectrometer consisting of Ge crystals and BGO shields. The neutron cross section measurements will be done at KUR linac and JAEA JRR-3M facilities, which will be extended at the high-intensity neutron source at J-PARC.

Journal Articles

Validation of the event generator mode in the PHITS code and its application

Iwamoto, Yosuke; Niita, Koji*; Sakamoto, Yukio; Sato, Tatsuhiko; Matsuda, Norihiro

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.2, p.945 - 948, 2008/05

The "Event Generator Mode" has been introduced into the PHITS code in the treatment of lower energy particles. In this mode, nuclear data for neutrons and a special evaporation model are combined so as to trace all higher correlations keeping the energy and the momentum conservation in a collision. This mode enables us to calculate the above-mentioned correlated quantities without any assumptions such as the pulse height tally adopted in the MCNP code, and also to estimate the Kerma factor and the DPA data without additional evaluated cross section libraries. In this work, we have calculated particle production cross sections, Kerma and DPA by using our developed event generator mode, and compared them with the evaluated nuclear data for the validation of the mode in neutron-induced reactions under 30 MeV. As an application of this mode, we will suggest a new approach to Kerma factor library weighted by quality factors for radiation protection against low energy neutron exposure.

Journal Articles

Measurement of the angle-correlated neutron spectrum for the $$^{9}$$Be(n,2n) reaction with a pencil-beam DT neutron source

Murata, Isao*; Takagi, Satoshi*; Shiken, Kimiaki*; Kondo, Keitaro; Miyamaru, Hiroyuki*; Ochiai, Kentaro; Nishitani, Takeo; Konno, Chikara

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.2, p.999 - 1002, 2008/05

The (n,2n) reaction plays a very important role in the design of fusion reactor. In the present study, using a pencil-beam DT neutron source, angle-correlated two neutrons emitted through (n,2n) reaction have directly been measured to determine (n,2n) reaction cross section with the coincidence detection technique for beryllium which is the most important element in the fusion reactor. In the experiment, two NE213 detectors were arranged very close to the sample to efficiently measure the two neutrons. The measured spectra were unfolded by FORIST with the detector response matrix evaluated by SCINFUL. As a relust, comparing with the evaluations of ENDF/B-VI and JENDL-3.3 for energies above 800 keV of the lower measurable limit energy, the shape of derived angula-differential cross-section fits JENDL-3.3 better than ENDF/B-VI. However, agreement of the cross section of (n,2n) above 800 keV was acceptable within 10 percents for both libraries.

Journal Articles

Recent advances in the JENDL project

Shibata, Keiichi; Nakagawa, Tsuneo; Fukahori, Tokio; Iwamoto, Osamu; Ichihara, Akira; Iwamoto, Nobuyuki; Kunieda, Satoshi; Otsuka, Naohiko; Katakura, Junichi; Watanabe, Yukinobu*; et al.

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.2, p.727 - 732, 2008/05

General- and special-purpose JENDL data files are being produced in cooperation with the Japanese Nuclear Data Committee. We have developed nuclear model codes to improve the quality of MA and FP data. In the FP region, we obtained global coupled-channel optical model parameters, which can be applied to neutron- and proton-induced reaction data up to 200 MeV. These parameters are used for statistical model calculation. Resolved resonance parameters of MA and FP nuclei were updated to improve the low-energy behavior of the cross sections by using recent measurements. As a follow-up of JENDL-3.3, which was released in 2002, covarainces of several nuclei were estimated for a study on ADS. Concerning special-purpose files, the compilation of the 2007 versions of JENDL High Energy File and Photonulcear Data Files is in the final stage.

Journal Articles

Benchmark of evaluated nuclear data libraries using post-irradiation experimental data on fuel composition changes of the fast reactor JOYO

Yokoyama, Kenji; Jin, Tomoyuki*

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.2, p.807 - 810, 2008/05

Post irradiation experiment (PIE) data on depleted fuel composition of the experimental fast reactor "JOYO" MK-II has been accumulated since 1986 in JNC (the former of JAEA). In the present study, all the available PIE data of JOYO MK-II driver fuel were analyzed and integral data concerning $$^{235}$$U depletion and $$^{236}$$U generation were prepared. Both the integral data are sensitive to $$^{235}$$U capture cross section and applicable to nuclear data benchmarks. The recent evaluated nuclear data libraries, JENDL-3.2, -3.3, JEFF-3.1 and ENDF/B-VII, have a tendency to overestimate the generation of $$^{236}$$U. A cross section adjustment demonstrated that re-evaluation of $$^{235}$$U capture cross section improved the overestimation.

Journal Articles

Validation of Np-237 cross sections by analysis of BFS critical experiments with massively neptunium-loaded cores

Ishikawa, Makoto; Hazama, Taira

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.2, p.817 - 820, 2008/05

Three series of BFS critical experiments which loaded approximately 10 kg of $$^{237}$$Np -dioxide were analyzed to verify the performance of major libraries with $$^{237}$$Np nuclear data. The latest JENDL-3.3, ENDF/B-VII.0 and JEFF-3.1 showed satisfactory results from the $$^{237}$$Np data viewpoint; however some other major data such as $$^{239}$$Pu nu and fission, $$^{238}$$U $$mu$$ and/or the sodium inelastic scattering cross-sections of some libraries may need re-evaluation. Further, the effect of integral experimental information to obtain better predictions of reactor core parameters was demonstrated by the cross-section adjustment method.

Journal Articles

Status and future work of the NEA working party on international nuclear data evaluation cooperation

Koning, A.*; Katakura, Junichi; Oblozinsk$'y$, P.*; Nichols, A. L.*; Nordborg, C.*

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.2, p.741 - 746, 2008/05

The Working party on international nuclear data Evaluation Cooperation (WPEC) is a collaborative effort between the major OECD nuclear data project: ENDF/B (USA), JENDL (Japan) and JEFF (Europe), and the IAEA-supported non-OECD project CENDL (China) and BROND (Russia). Nuclear data challenges and problems that are common to all projects are considered in various WPEC subgroups that are normally pf limited time span. The achievements of these subgroups are reviewed in this paper. Among the recent accomplishments are improved criticality predictions through revised U evaluations, the completion of new cross-section standards, and the creation of a new Fission Product library. Problems that are currently being addressed are the processing and inclusion of covariance data in the libraries, improvements in decay data to assist in decay heat calculations, assembly of a well-structured High Priority Request List, validation of the new fission product cross-section library, and the assessment of nuclear data needs for GEN-IV.

Journal Articles

Integrated nuclear data utilization system for innovative reactors; Nuclear data processing and utilization system

Yamano, Naoki*; Katakura, Junichi; Kato, Kiyoshi*; Igashira, Masayuki*

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.2, p.825 - 828, 2008/05

A nuclear data processing and utilization system has been developed as a modular code system of the integrated nuclear data utilization system for innovative nuclear energy system. The system is able to handle evaluated nuclear data in ENDF-6 format to generate point-wise and group-wise cross sections in several formats, and has a capability to perform criticality and shielding benchmarks. An overview of the integrated nuclear data utilization system and the scheme of cross-section generation and benchmark procedure in the system have been described as well as future development plan based on the system.

Journal Articles

Development needs of nuclear data for fusion technology

Fischer, U.*; Batistoni, P.*; Forrest, R. A.*; Konno, Chikara; Perel, R. L.*; Seidel, K.*; Simakov, S. P.*

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.2, p.973 - 978, 2008/05

An overview is presented of the nuclear data required for nuclear design analyses of fusion technology focusing on ITER, the International Thermonuclear Experimental Reactor, and IFMIF, the International Fusion Materials Irradiation Facility. The status of the available data evaluations and libraries is reviewed with regard to the required materials/nuclides and data types and, in particular, with regard to their quality as compared to differential and integral experimental data. Future development needs are identified on this basis addressing nuclear data evaluations for neutron and photon transport simulations, cross-section data for activation and transmutation calculations, and co-variance data for uncertainty analyses.

Oral presentation

Half-life of $$^{184}$$Re populated by photodisintegration reaction with Laser Compton scattering $$gamma$$-rays at NewSUBARU

Hayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.

no journal, , 

no abstracts in English

Oral presentation

The Design and construction of a spectrometer to efficiently identify nuclear levels

Furutaka, Kazuyoshi; Oshima, Masumi; Kimura, Atsushi; Toh, Yosuke; Koizumi, Mitsuo; Kin, Tadahiro; Goto, Jun*

no journal, , 

Simulation study was performed to choose an optimal configuration of a $$gamma$$-ray spectrometer consisting of Ge and BGO detectors, which facilitates identification of prompt $$gamma$$ rays to ground states emitted following capture reactions of neutrons in thermal energy region and determination of the reaction cross sections.

Oral presentation

Performance of a data acquisition system for a large germanium detector array

Kimura, Atsushi; Koizumi, Mitsuo; Toh, Yosuke; Goto, Jun*; Oshima, Masumi

no journal, , 

We have evaluated performance of our new data acquisition system, which utilizes digital signal processing techniques and was developed for a 4$$pi$$ Ge spectrometer. Total energy resolution of this system was 2.5 keV in FWHM for 1.33-MeV $$gamma$$ rays and 16.4 keV in FWHM for 10.83-MeV prompt $$gamma$$ rays. The time resolution of timing signals, which are used for the measurements of coincident $$gamma$$ rays, was 120 ns in FWHM. Those values fulfilled our requirements for the DAQ system. A method of dead time correction with this system was also developed.

19 (Records 1-19 displayed on this page)
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