Cryogenically cooled monochromator with multi-crystal switching system on BL11XU at SPring-8

Shiwaku, Hideaki   ; Mitsui, Takaya; Tozawa, Kazukiyo*; Kiriyama, Koji*; Harami, Taikan; Mochizuki, Tetsuro*

We developed a multi-crystal switching system on a cryogenically cooled monochromator of JAERI materials science beamline, BL11XU. In order to study our science, it is necessary for ensuring at least the energy range of 6 - 70keV to employ Si(111) and Si(311) crystals. The principle of the crystal switching is that, two pair of crystals is arranged side by side, and they are translated in horizontal direction for exchanging. Indium sheets were inserted between both sides of crystals in order to improve thermal contact. Some adjustment stages of the monochromator were removed to avoid the crystal vibration and a sheet heater was installed on an X-axis stage to prevent over-cooling of X-axis stages. The monochromator is under commissioning at present. In comparison with a previous indirect water cooling diamond (111) crystal monochromator, this monochromator provides high flux intensity from 4 times to 7 times. It takes only 5 minutes to exchange and adjust crystals geometry. This mechanism will be easily applied to other crystals, for example asymmetrical-cut crystals.