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Kajimoto, Ryoichi; Nakajima, Kenji; Nakamura, Mitsutaka; Osakabe, Toyotaka; Sato, Taku*; Arai, Masatoshi
Journal of Neutron Research, 16(3-4), p.81 - 86, 2008/09
Cold Neutron Double-Chopper Spectrometer (CNDCS) is under construction for the spallation neutron source at Materials and Life Science Facility (MLF), Japan Proton Accelerator Research Complex (J-PARC). It is dedicated for research of inelastic phenomena with low energy transfer utilizing an incident energy of meV. It has a 30 m moderator-sample distance () and a supermirror-coated neutron guide tube between the moderator and the sample. The guide tube is curved to eliminate unwanted fast neutron and ray emitted immediately after a proton hits the target. In the present paper, we present the performance of the curved guide of CNDCS obtained by Monte Carlo simulation using McStas. We will report energy dependence of gain in intensity and beam distributions for several kinds of supermirrors, in comparison to the case utilizing a chopper and a straight guide.
Nakamura, Mitsutaka; Arai, Masatoshi; Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakajima, Kenji; Krist, T.*
Journal of Neutron Research, 16(3-4), p.87 - 92, 2008/09
no abstracts in English
Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakajima, Kenji; Nakamura, Mitsutaka; Inamura, Yasuhiro; Soyama, Kazuhiko; Ino, Takashi*; Oyama, Kenji*; Sakai, Makiko; Aizawa, Kazuya; et al.
no journal, ,
4SEASONS is one of the day-one chopper spectrometers for the spallation neutron facility in Japan Proton Accelerator Research Complex (J-PARC). The spectrometer targets high- superconductors and related strongly correlated materials utilizing incident energies of 5-300 meV. 4SEASONS supplies high flux at a sample by moderating the resolution (-6% at ) and incorporating efficient neutron optic devices. A new Fermi chopper is designed to multiply the measurement efficiency by repetition rate multiplication (RRM). Recently, we have decided to enlarge the detector coverage by in horizontal direction (with the maximum scattering angle being ) to let the spectrometer have more flexibility. The designing of the vacuum scattering chamber has been almost completed. Examination of the 2.5m-He PSD on neutron beam and manufacturing of a prototype of a slit package of the new chopper are going on.