Design of engineering diffractometer at J-PARC

Harjo, S.   ; Moriai, Atsushi; Torii, Shuki; Suzuki, Hiroshi  ; Suzuya, Kentaro; Morii, Yukio; Arai, Masatoshi; Tomota, Yo*; Akita, Koichi*; Akiniwa, Yoshiaki*

An engineering diffractometer designed to solve many problems in materials science and engineering including investigations of stresses and crystallographic structures within engineering components is now being developed at J-PARC project. This instrument views a decoupled-poisoned liquid H moderator, and the primary and the secondary flight paths are 40 m and 2.0 m, respectively, for 90 degree scattering detector banks. The optimization of this instrument has been performed with a Monte Carlo simulation, and an appropriate resolution of less than 0.2 % in d/d has been confirmed. A prototyped radial collimator to define a gauge width of 1 mm has been designed and manufactured. From performance tests conducted at the neutron diffractometer for residual stress analysis RESA, the normal distribution with a full width at half maximum of 1.0 mm was obtained in a good agreement with the simulation.