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Shibata, Kaoru
Hamon, 28(1), p.26 - 28, 2018/02
We briefly introduce the pedigree of the backscattering neutron spectrometer and the specification of DNA; a time-of-flight (TOF) type near-backscattering spectrometer (n-BSS), with Si crystal analyzers which was constructed at the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC).
Yamazaki, Dai; Soyama, Kazuhiko; Ebisawa, Toru*; Takeda, Masayasu; Maruyama, Ryuji*; Tasaki, Seiji*
Physica B; Condensed Matter, 356(1-4), p.174 - 177, 2005/02
Times Cited Count：1 Percentile：6.21(Physics, Condensed Matter)Drabkin energy filter could be used as a fast chopper for pulsed neutrons by varying the resonant wavelength 
fast in such a way that resonant wavelength matches neutron wavelength at a small time region. The faster are varied, the smaller time window we could obtain. Neutron pulses could be sharpened much more effectively for a small wavelength band than in the wide-band pulse-shaping mode in which is varied in synchronization with the time-of-flight from the moderator. In our preliminary test of a chopper-mode with a prototype Drabkin energy filter, time-window of 0.21 ms was obtained while it was 1.08 ms with the filter driven stationary. Narrower time-window could have been obtained if we had more beam-time and it could be also narrowed with higher-resolution Drabkin filters.
Yokoyama, Keiichi; Teranishi, Yoshiaki; Toya, Yukio; Shirai, Toshizo; Fukuda, Yuji; Aoyama, Makoto; Akahane, Yutaka; Inoue, Norihiro*; Ueda, Hideki; Yamakawa, Koichi; et al.
Journal of Chemical Physics, 120(20), p.9446 - 9449, 2004/05
Times Cited Count：6 Percentile：18.74(Chemistry, Physical)Optimal laser control for ultrafast selection of closely-lying excited states, whose energy separation is smaller than the laser bandwidth, is reported on the two-photon transition of atomic cesium; Cs(6S 
7D
, J = 5/2 and 3/2). Selective excitation was carried out by pulse shaping of ultrashort laser pulses which were adaptively modulated in a closed-loop learning system handling eight parameters representing the electric field. Two-color fluorescence from the respective excited states was monitored to measure the selectivity. The fitness used in the learning algorithm was evaluated from the ratio of the fluorescence yield. After fifty generations, a pair of nearly transform-limitted pulses were obtained as an optimal pulse shape, proving the effectiveness of "Ramsey fringes" mechanism. The contrast of the selection ratio was improved by 
30 % from the simple "Ramsey fringes" experiment.
Yamazaki, Dai
Hamon, 14(2), p.130 - 133, 2004/04
no abstracts in English
Yamazaki, Dai; Soyama, Kazuhiko; Ebisawa, Toru*; Tamura, Itaru; Tasaki, Seiji*
Proceedings of ICANS-XVI, Volume 1, p.407 - 415, 2003/06
Drabkin energy filters extract neutrons of required wavelength using spatial neutron spin resonance. If they are applied to pulsed neutrons, they could sharpen pulse width and cut tail neutrons without reducing band-width or peak-intensity. Shaping of J-PARC coupled-moderator pulse by a Drabkin energy filter was simulated. In the simulation, discrete field gradient to Bx is introduced and total field B is varied in accordance with the dominant wavelength at each moment at the filter position. The results suggest that about 90 % or more of tail neutrons from coupled moderator are cut and a fliter with fields of 200 periods could reduce pulse width up to that of decoupled moderator. Effects of fluctuations of width of each half period were studied and it was found that fluctuation within 
1 % are tolerable for a flipper with field of 100 or 200 periods.
Shibata, Kaoru; Kawakita, Yukinobu; Nakagawa, Hiroshi; Yamada, Takeshi*; Tominaga, Taiki*; Matsuura, Masato*
no journal, ,
A time-of-flight (TOF) type near-backscattering spectrometer (n-BSS), DNA was built and started operation in 2012 at the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). It offers a high-energy resolution of about 1.6 micro eV and very wide energy scan range: -400 
E/[micro eV] +600 with signal-to-noise ration of 
100,000. Those factors gave big advantage to enlarge application fields to dynamical behaviors of atoms and spins in bio-molecules, soft-materials and strongly-correlated electron system in nanosecond timescale or in micro-eV energy region.
