Evaluation of two-stage system for neutron measurement aiming at increase in count rate at Japan Atomic Energy Agency - Fusion Neutronics Source

Shinohara, Koji; Ishii, Keiichi*; Ochiai, Kentaro; Baba, Mamoru*; Sukegawa, Atsuhiko; Sasao, Mamiko*; Kitajima, Sumio*

Review of Scientific Instruments, 85(11), p.11E823_1 - 11E823_4, 2014/11

https://doi.org/10.1063/1.4893941

Study of neutron and photon production cross sections for second cancer risk assessment in heavy-ion therapy

Uozumi, Yusuke*; Iwamoto, Hiroki*; Koba, Yusuke*; Matsufuji, Naruhiro*; Sanami, Toshiya*; Satoh, Daiki; Shigyo, Nobuhiro*; Takada, Masashi*; Ueyama, Masahiko*; Yoshioka, Masakatsu*; et al.

Progress in Nuclear Science and Technology (Internet), 1, p.114 - 117, 2011/02

https://doi.org/10.15669/pnst.1.114

It is important to assess and suppress the potential for second cancer induction by secondary neutrons produced in primary heavy-ion fragmentation in patient body. Since it is very difficult to measure high-energy neutron doses in mixed radiation fields, a Monte-Carlo simulation approach has attracted much attention as an alternative for neutron dose estimation. It is notoriously hard to reproduce the spectral cross sections of neutrons from high-energy heavy-ion collisions. We, therefore, have planned experiments to measure energy-angle double-differential cross sections of nuclear reactions.

Fast neutron- discrimination on neutron emission profile measurement on JT-60U

Ishii, Keiichi*; Shinohara, Koji; Ishikawa, Masao; Baba, Mamoru*; Isobe, Mitsutaka*; Okamoto, Atsushi*; Kitajima, Sumio*; Sasao, Mamiko*

Review of Scientific Instruments, 81(10), p.10D334_1 - 10D334_3, 2010/10

https://doi.org/10.1063/1.3496986

High repetition rate neutron flux array using digital-signal processing and scintillators for study of high performance plasma at JT-60U

Shinohara, Koji; Okuji, Toshio*; Ishikawa, Masao; Baba, Mamoru*; Itoga, Toshiro*

Review of Scientific Instruments, 79(10), p.10E509_1 - 10E509_4, 2008/10

https://doi.org/10.1063/1.2971975

Confinement degradation and transport of energetic ions due to Alfvn eigenmodes in JT-60U weak shear plasmas

Ishikawa, Masao; Takechi, Manabu; Shinohara, Koji; Cheng, C. Z.*; Matsunaga, Go; Kusama, Yoshinori; Fukuyama, Atsushi*; Nishitani, Takeo; Morioka, Atsuhiko; Sasao, Mamiko*; et al.

Nuclear Fusion, 47(8), p.849 - 855, 2007/08

https://doi.org/10.1088/0029-5515/47/8/016

Confinement degradation of energetic ions due to Alfvn Eigenmodes (AEs) induced by negative-ion-based neutral beam injection for the classical confinement is quantitatively evaluated for the first time. AEs, whose frequency largely sweep and then saturate as the minimum value of the safety factor decrease, have been observed in JT-60U. These mode behavior can be explained by RSAEs and the transition from RSAEs to TAEs. Measured total neutron emission rate in the presence of these AEs is compared with that predicted by a classical theory. As a result, confinement degradation of energetic ions is confirmed. Line-integrated neutron emission profile is also compared with that predicted when assuming that the confinement is classical. The result indicates energetic ions are transported from core region of the plasma due to these AEs.

Advanced diagnostics for burning plasma experiments

Sasao, Mamiko*; Yamada, Hiroshi*; Baba, Mamoru*; Kondoh, Takashi; Peterson, B. J.*; Kawahata, Kazuo*; Mase, Atsushi*; Yoshikawa, Masayuki*; Azechi, Hiroshi*; Toi, Kazuo*; et al.

Fusion Science and Technology, 51(2T), p.40 - 45, 2007/02

https://doi.org/10.13182/FST07-A1310

Several unexplored physics issues will be studied in burning plasma experiments, planned on ITER in the near future. To carry out these studies, it is essential to develop novel diagnostic systems, such as fusion product measurement systems and high-resolution, high-reliability profile measurement of various plasma parameters. Scientific research on "Advanced Diagnostics for Burning Plasma Experiment" was assigned as a priority area by MEXT in 2004, and more than 20 studies are currently underway under this program. The feasibility of several new diagnostic concepts applicable to ITER is examined and diagnostic components for these systems are now under development.

Measurement of neutron spectra produced in the forward direction from thick graphite, Al, Fe and Pb targets bombarded by 350 MeV protons

Iwamoto, Yosuke; Taniguchi, Shingo*; Nakao, Noriaki*; Itoga, Toshio*; Nakamura, Takashi*; Nakane, Yoshihiro; Nakashima, Hiroshi; Satoh, Daiki; Yashima, Hiroshi*; Yamakawa, Hiroshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 562(2), p.789 - 792, 2006/06

https://doi.org/10.1016/j.nima.2006.02.056

Neutron energy spectra produced from thick targets play an important role in validation of calculation codes that are employed in the design of spallation neutron sources and the shielding design of accelerator facilities. However, appropriate experimental data were scarce in the forward direction for the incident energy higher than 100 MeV. In this study, neutron spectra at 0 degree from thick targets bombarded with 350 MeV protons were measured by the time-of-flight technique using an NE213. The targets used were graphite, Al, Fe and Pb and their thicknesses were chosen to be a little thicker than the stopping lengths. The experiment was carried out at the TOF course of the RCNP (Research Center of Nuclear Physics) ring cyclotron, Osaka University. The flight path length between center of the target and of an NE213 were 11.4 m for the measurement of low energy neutrons and 95 m for high energy neutrons. The experimental data are compared with the calculated results by using the Monte Carlo transport codes, such as MCNPX and PHITS codes.

Evaluations of heavy nuclide data for JENDL-3.3

Kawano, Toshihiko*; Matsunobu, Hiroyuki*; Murata, Toru*; Zukeran, Atsushi*; Nakajima, Yutaka*; Kawai, Masayoshi*; Iwamoto, Osamu; Shibata, Keiichi; Nakagawa, Tsuneo; Osawa, Takaaki*; et al.

JAERI-Research 2003-026, 53 Pages, 2003/12

JAERI-Research-2003-026.pdf:2.48MB

New evaluations of neutron nuclear data for Uranium, Plutonium, and Thorium isotopes which are essential for applications to nuclear technology were carried out for the Japanese Evaluated Nuclear Data Library, JENDL-3.3. The objectives of the current release of JENDL were to fix several problems which have been reported for the previous version, to improve the accuracy of the data, and to evaluate covariances for the important nuclides. Quantities in JENDL-3.2 were extensively re-evaluated or replaced by more reliable values. The heavy nuclide data in JENDL-3.3 were validated with several benchmark tests, and it was reported that the current release gave a good prediction of criticalities.

Japanese evaluated nuclear data library version 3 revision-3; JENDL-3.3

Shibata, Keiichi; Kawano, Toshihiko*; Nakagawa, Tsuneo; Iwamoto, Osamu; Katakura, Junichi; Fukahori, Tokio; Chiba, Satoshi; Hasegawa, Akira; Murata, Toru*; Matsunobu, Hiroyuki*; et al.

Journal of Nuclear Science and Technology, 39(11), p.1125 - 1136, 2002/11

https://doi.org/10.3327/jnst.39.1125

Evaluation for JENDL-3.3 has been performed by considering the accumulated feedback information and various benchmark tests of the previous library JENDL-3.2. The major problems of the JENDL-3.2 data were solved by the new library: overestimation of criticality values for thermal fission reactors was improved by the modifications of fission cross sections and fission neutron spectra for U; incorrect energy distributions of secondary neutrons from important heavy nuclides were replaced with statistical model calculations; the inconsistency between elemental and isotopic evaluations was removed for medium-heavy nuclides. Moreover, covariance data were provided for 20 nuclides. The reliability of JENDL-3.3 was investigated by the benchmark analyses on reactor and shielding performances. The results of the analyses indicate that JENDL-3.3 predicts various reactor and shielding characteristics better than JENDL-3.2.

Measurement of fission cross section and fission neutron spectrum of Np-237 by an advanced technique

*

JNC TJ9400 2000-007, 46 Pages, 2000/03

JNC-TJ9400-2000-007.pdf:2.16MB

For fission cross section and prompt fission neutron spectrum, which largely influence core characteristics of a fast reactor, we have performed experimental and analytical studies for developing an advanced technique to measure absolute fission cross section and neutron fission spectrum for actinide nuclides such as Np237. As the results, we could develop an advanced technique, which combines a normalization technique for the well-known differential cross section and a correction method by a Monte-Carlo code for sample effects. This advanced technique accurately provides both absolute fission cross section and prompt fission neutron spectrum individually. By employing this technique, in this study, we have measured for three actinides (Np, Th and U), then, have obtained the fission cross sections and fission spectrum parameter data for those nuclides. Furthermore, we have also performed an analytical study to examine sensitivity of fission spectrum parameter to core multiplication factor by using the standard calculation code for a first reactor.