Ibaraki biological crystal diffractometer in J-PARC (BIX-P1); Optimization of design parameters

Kusaka, Katsuhiro; Ohara, Takashi   ; Tanaka, Ichiro*; Niimura, Nobuo*; Ozeki, Tomoji*; Kurihara, Kazuo; Aizawa, Kazuya  ; Morii, Yukio; Arai, Masatoshi; Ebata, Kazuhiro*; Takano, Yoshiki*

The TOF neutron biological diffractometer in J-PARC proposed by Ibaraki prefectural government is designed to cover the samples have their cell edges up to 135A, and to realize the efficiency is more than 50 times larger than the present high performance diffractometer, BIX-4. To achieve this performance, the diffractometer will be installed on a coupled moderator has more intense peak but wider pulse shape. The overlapping of Bragg spots along the time-axis expected should be considered for the determination of optic parameters and it is necessary to de-convolute the overlapped spots with higher accuracy. The original simulation programs of TOF diffraction data were developed to obtain information of spot-overlapping, completeness of Bragg spots and spot profiles along time-axis. In this paper, the consideration of important designed parameters focused on biological macromolecular and the strategy of de-convoluting overlapped spots will be reported based on the simulation results.