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TY - UNPB AU - Kristiansen, P. ED - Casas, Joan ED - Schaa, Volker RW ED - Costa, Isidre ED - López, David ED - Prieto, Montserrat TI - Vibrational Stability of a Cryocooled Horizontal-Bounce Double Crystal Monochromator J2 - Proc. of MEDSI2016, Barcelona, Spain, 11-16 September 2016 CY - Barcelona, Spain T2 - Mechanical Engineering Design of Synchrotron Radiation Equipment and Instrumentation Conference T3 - 9 LA - english AB - There is an increasing demand on monochromators to preserve the performance of the latest ultra-stable storage rings. One method of obtaining near-complete vertical preservation of the ring stability is to arrange the crystals in a horizontal diffracting geometry. We present the vibrational performance of a fixed offset Horizontal Double Crystal Monochromator. We have made direct measurements, at cryocooled conditions, on a H-DCM currently deployed at MAX IV that has a relative pitch stability of 25 nrad RMS, 1-2500 Hz, and an absolute pitch stability of 18 nrad RMS, 2-2500 Hz, when running the cryocooler in a condition that allows 1.5kW to be extracted via the circulating liquid nitrogen. These results demonstrate the advantage in terms of vibrational stability of circulating the liquid nitrogen high pressures, which enables the flow velocities to be reduced to obtain equivalent cooling performance. The value of performing live measurements is illustrated as we show that a vibration of the in-vacuum cryoline support structure is not translated into relative crystal vibrations, contrary to the intuitive assumption that this would be the primary source of beam instability. PB - JACoW Publishing CP - Geneva, Switzerland ER -