Naoki Kawata
Tohoku University
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Featured researches published by Naoki Kawata.
Fusion Science and Technology | 2005
M. Hagiwara; T. Itoga; Naoki Kawata; N. Hirabayashi; T. Oishi; T. Yamauchi; M. Baba; M. Sugimoto; T. Muroga
Abstract To improve the data accuracy of the neutron emission spectra of the natLi(d,xn) reaction that will be used as the neutron source in the International Fusion Materials Irradiation Facility, the authors have measured the neutron emission spectra from thick and thin lithium targets bombarded by 40-MeV deuterons at the AVF cyclotron (K = 110) facility of Tohoku University. The neutron spectra were measured at nine laboratory angles between 0 and 110 deg with the time-of-flight method using a beam-swinger system and a well-collimated neutron flight channel, obtained over almost the entire energy range of secondary neutrons using a two-gain method. The data obtained revealed the shape and angular dependence of emission spectra up to the high-energy region called a “high-energy tail.” The experimental results are compared with other experimental data and calculations.
Journal of Nuclear Materials | 2002
M. Baba; Takao Aoki; M. Hagiwara; M. Sugimoto; Takako Miura; Naoki Kawata; A. Yamadera; H Orihara
To improve the data accuracy of the neutron emission spectrum of the 7 Li(d,n) reaction and the radioactivity ( 7 Be, 3 H, etc.) accumulated in the 7 Li target in IFMIF, we have measured the neutron emission spectrum and the radioactivity of Be induced in the lithium target for 25 MeV deuterons at the Tohoku University AVF cyclotron (K = 110) facility. Neutron spectra were measured with the time-of-flight (TOF) method at four laboratory angles by using a beam swinger system and a well collimated TOF channel. Induced radioactivity was measured by detecting the gamma-rays from Be with a pure Ge detector. Experimental results are compared with other experimental data. The present result of neutron emission spectra are in qualitative agreement with other experimental data but that of 7 Be production was much larger than expected by the recent codes. Measurement will be extended to several incident energies up to 40 MeV.
Journal of Nuclear Science and Technology | 2004
Takao Aoki; M. Hagiwara; Mamoru Baba; M. Sugimoto; Takako Miura; Naoki Kawata; A. Yamadera
Neutron emission spectra and production rates of radioactive nuclide 7Be in the (d, n) reactions on thick lithium and 9Be targets have been measured for 25 MeV deuterons at the Tohoku University AVF cyclotron (K=110) facility to provide basic data for the design of the intense neutron source, International Fusion Reactor Material Irradiation Test Facility (IFMIF). Neutron spectra were measured with the time-of-flight method at ten laboratory angles between 0° and 90° by using a beam swinger system. Data were obtained down to ~1 MeV from the highest energy, using a two-gain NE213 detector system. Induced radioactivity of 7Be was measured by detecting the 478 keV γ-rays from 7Be with a pure Ge detector. The experimental results of neutron spectra revealed clearly the entire shape of the neutron emission spectrum and the angular dependence including so called “high energy tail” extending up to ~40 MeV. The present data at 0° are in reasonable agreement with corresponding value by Lone et al. at 23 MeV above ~5 MeV, but show large discrepancy in the lower energy region. The results of 7Be production for both nuclei were much larger than expected by the calculation with a recent code IRAC.
Journal of Nuclear Science and Technology | 2002
Toshiya Sanami; Tsutomu Hiroishi; Mamoru Baba; M. Hagiwara; Takako Miura; Takao Aoki; Naoki Kawata; Susumu Tanaka; Hiroshi Nakashima; Shin-ichiro Meigo; Masashi Takada
Double differential (n,xp), (n,xd), (n,xt) and (n,xα) cross sections of oxygen and nitrogen were measured for 75 MeV incident neutrons at 25°, 65° and 125° angles using a specially designed spectrometer. The spectrometer has three counter telescope consisting of a low pressure gas proportional counter, a thin SSD and a BaF2 scintillator. The energy dependence of the BaF2 was calibrated with direct proton, deuteron and helium beams. The results were compared with the LA-150 data library. The library represents the experimental results of proton, triton and α-particle generally well, but shows the marked difference in the high energy part of deuteron one.
INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY | 2005
T. Itoga; M. Hagiwara; Naoki Kawata; Takeshi Yamauchi; N. Hirabayashi; T. Oishi; Mamoru Baba
Differential thick target neutron yields (TTY) for natFe, natCu(p,xn) reactions were measured for 35, 50 and 70 MeV incident energy at several laboratory angles between 0‐ and 110‐deg. using the time‐of‐flight method with the Tohoku Univ. AVF cyclotron and a beam‐swinger system. We determined neutron energy spectra from ∼ 0.6 MeV to the highest secondary neutron energy. The experimental results were compared with the LA150 data library.
Journal of Nuclear Science and Technology | 2014
M.S. Uddin; Masayuki Hagiwara; Naoki Kawata; T. Itoga; N. Hirabayashi; M. Baba; F. Tárkányi; F. Ditrói; J. Csikai
CYRIC annual report | 2000
Takako Miura; Mamoru Baba; Naoki Kawata; Takao Aoki; Masayuki Hagiwara; Tsutomu Hiroishi; Toshiya Sanami; T. Nishitani; J. Hori
Archive | 2003
T. Itoga; Naoki Kawata; M. Hagiwara; N. Hirabayashi; Mamoru Baba; T. Nishitani; K. Ochiai
CYRIC annual report | 2003
T. Itoga; M. Hagiwara; T. Yamauchi; T. Ohishi; Naoki Kawata; N. Hirabayashi; Mamoru Baba
CYRIC annual report | 2002
Masayuki Hagiwara; Mamoru Baba; Naoki Kawata; T. Itoga; N. Hirabayashi