Neutron diffractometer encompassing protein crystals with large unit cell volume at J-PARC

Kurihara, Kazuo; Tomoyori, Katsuaki; Tamada, Taro; Kuroki, Ryota

Many proteins, especially membrane proteins and protein complexes, have larger molecular weight and then unit cells of their crystals have larger volume. Therefore, our group had designed the diffractometer which can cover such crystals with large unit cell volume (target lattice length: 250) at J-PARC. In order to separate spots closer to each other in spatial as well as time dimension in diffraction images, our proposed diffractometer adopts longer camera distance (2 = 800mm) and selects decoupled hydrogen moderator as neutron source which has shorter pulse width. Under the conditions that 1 is 33.5m, beam divergence 0.4 and crystal edge size 2mm, this diffractometer is estimated to afford the resolution () of 1% at the middle and high 2 angles and be able to resolve spots diffracted from crystals with a lattice length of 220 in each axis at -space of 2.0. In order to increase measurement efficiency, novel large-area detector (larger than 300mm 300mm) with a spatial resolution of better than 2.5mm is under development. More than 40 detectors plan to be installed, providing the total solid angle coverage of larger than 33%.