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TY - CONF AU - Tanimoto, Y. AU - Honda, T. AU - Jin, X.J. AU - Nogami, T. AU - Takai, R. AU - Yamamoto, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Vacuum Performance of the NEG-coated Chamber for U#19 at PF-ring J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - At the Photon Factory storage ring (PF-ring) in KEK, a new APPLE-II type elliptically polarizing undulator (U#19) was installed in October 2018. The U#19 vacuum chamber is 4.1 meters in length, and the beam channel with a 15x90 elliptical profile and two cooling-water channels alongside were formed by extrusion of A6060-T6 aluminum alloy. The inner surface of the beam channel is coated with a Ti-Zr-V Non-Evaporable Getter (NEG) thin film, as it has a high effective pumping speed and a low Photon Stimulated Desorption (PSD) yield. After the installation of the U#19, the neighboring uncoated chambers and vacuum components were baked out at 200 °C for 44 hours, and then the NEG coating was activated at 160 °C for 48 hours. As a result, the pressures in the neighboring chambers reached as low as 10⁻⁸ Pa. The conditioning of the vacuum chambers with irradiation of Synchrotron radiation evolved favorably as had been expected by a combined simulation of Synrad and Molflow, leading to a satisfactory recovery of the beam lifetime. Vacuum performance of the NEG-coated chamber was assessed especially by means of a residual gas analysis, and the properties of the NEG film were characterized by surface analyses including SEM, EDX, and XRD. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1276 EP - 1279 KW - vacuum KW - photon KW - simulation KW - MMI KW - undulator DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPMP019 UR - http://jacow.org/ipac2019/papers/tupmp019.pdf ER -