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TY - UNPB AU - Yamazaki, H. AU - Ikeya, Y. AU - Kishimoto, H. AU - Matsuzaki, Y. AU - Miura, T. AU - Ohashi, H. AU - Senba, Y. AU - Shimizu, Y. AU - Takeuchi, T. AU - Tanaka, M. AU - Tsuboki, I. ED - Schaa, Volker RW ED - Tavakoli, Keihan ED - Tilmont, Manuel TI - Refinements of SPring-8 Standard Monochromators with Cryogenically Cooled Silicon Crystals toward 50 nrad-Stability J2 - Proc. of MEDSI2018, Paris, France, 25-29 June 2018 C1 - Paris, France T2 - Mechanical Engineering Design of Synchrotron Radiation Equipment and Instrumentation T3 - 10 LA - english AB - In SPring-8, 21 of the 28 X-ray undulator beamlines have the same sets of a double-crystal monochromator (DCM) and a cryogenically cooling system. A remaining problem is vibration for the forthcoming upgraded SPring-8. For certain experiments, vibration seems to fluctuate the source position. The virtual fluctuation, which increases the effective source size, degrades high-density nanobeam made by direct projection of the source. When a DCM is placed at 40 m downstream from a source with 6-um size, the vibration should be 50 nrad to suppress 20%-increase of the source size. The vibration was over 800 nrad in 2011. We have continued improving low-vibration flexible tubes for transport tube of liquid nitrogen, high-rigidity tilt stages, and temperature controllers of the coolant. The latest-version refinements were carried out to 5 DCMs in 2017FY. The vibrations were reduced to about 110 nrad in 4 DCMs and 55 nrad for one. PB - JACoW Publishing CP - Geneva, Switzerland ER -