The new neutron powder diffractometer with a multi-detector system for high-efficiency and high-resolution measurements

We describe a multipurpose neutron powder diffractometer for high-efficiency and high-resolution measurements, HERMES, which has been installed at the JRR-3M reactor in Japan Atomic Energy Research Institute. To obtain high-quality data for a short counting time, or with a small sample amount, HERMES has a multi-detector system which consists of 150 He-3 neutron detectors and simple window type collimation. The best resolution is Delta 2 theta of 18' and Delta d/d of 3 x 10(-3), where 2 theta and d are scattering-angle and d-spacing, respectively. The duration of an ordinary powder diffraction experiment is 1-5 h under the present conditions in JRR-3M. Some typical results of powder diffraction experiments and performance are given in this paper. We also show a result of 2D intensity mapping of magnetic diffuse scattering from a single crystal of a spin glass material.