Stabilizing methods for mechanical vibrations on cryogenically cooled monochromator on BL11XU at SPring-8

Kiriyama, Koji*; Shiwaku, Hideaki   ; Mochizuki, Tetsuro*; Shobu, Takahisa*  ; Tozawa, Kazukiyo*

Multi-stabilizing methods for vibrations on the cryogenically cooled monochromator have been tried on BL11XU at SPring-8. Observed vibrations on crystals were mainly 1-10 Hz, 30 Hz, and 50 Hz. The results suggested that sources of the vibrations were liquid nitrogen flow and propagation from vibrations of vacuum pumps equipped with beam line. We took countermeasures of the vibrations to liquid nitrogen tubes, and set parameters (temperature, pressure and flow-late) of the cryogenic cooling system for 1-10 Hz vibration. Vibration absorber was set not to propagate the vibrations from the vacuum pumps and their fans for 30 and 50 Hz vibrations. These methods successfully removed the mechanical vibrations. Then, intensity vibration of X-ray was decreased from 4.47 % to 0.85 %, in the end. The stabilizing methods on BL11XU are expected to apply to the similar system at the other beam-lines.