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TY - CONF AU - Volpe, L.M. AU - Corsaletti, J.C. AU - Francisco, B.A. AU - Geraldes, R.R. AU - Silva, M.S. ED - Jaski, Yifei ED - Den Hartog, Patric ED - Jaje, Kelly ED - Schaa, Volker R.W. TI - Thermal Model Validation for the Cryogenic Mirror Systems for Sirius/LNLS J2 - Proc. of MEDSI2020, Chicago, IL, USA, 24-29 July 2021 CY - Chicago, IL, USA T2 - Mechanical Engineering Design of Synchrotron Radiation Equipment and Instrumentation T3 - 11 LA - english AB - One of the challenges of fourth-generation synchrotron light sources as Sirius at the Brazilian Synchrotron Light Laboratory (LNLS) is the high power density that may affect the beamline optical elements by causing figure deformations that deteriorate the quality of the beam. Indeed, surface specifications for height errors of X-ray mirrors are often within a few nanometers. To deal with these thermal management challenges, thermo-mechanical designs based on cryogenic silicon have been developed, taking advantage of its high thermal conductance and low thermal expansion in temperatures of about 125 K. A liquid nitrogen (LN2) cryostat connected to the optics by copper braids has been used to handle moderate power loads, reducing costs when compared to closed-circuit LN2 cryocoolers and mechanically decoupling flow-induced vibrations from the optics. To guarantee the functionality of such systems, lumped mass thermal models were implemented together with auxiliary finite elements analyses. With the first systems in operation, it has been possible to compare and validate the developed models, and to carry out optimizations to improve them for future projects, by adjusting parameters such as emissivity, thermal contact resistance, and copper braid conductance. This work presents the updated models for CARNAÚBA and CATERETÊ beamlines as reference cases. PB - JACoW Publishing CP - Geneva, Switzerland SP - 320 EP - 323 KW - synchrotron KW - experiment KW - radiation KW - cryogenics KW - optics DA - 2021/10 PY - 2021 SN - 2673-5520 SN - 978-3-95450-229-5 DO - doi:10.18429/JACoW-MEDSI2020-WEPC07 UR - https://jacow.org/medsi2020/papers/wepc07.pdf ER -