CLS HXMA 2.0 T superconducting Wiggler upgrades

The 2.0 T superconducting (SC) Wiggler on the CLSI Hard X-ray Micro Analysis (HXMA) beamline [1-2] ran at a field of 1.9 Tesla during normal operation, lower than the design specification. After ten years of operation, CLSI experienced significant downtime and wiggler magnetic field decreasing due to frequent breakdowns at the cryogenic system [3]. There were total of three emergency repairs at the cryo-cooler and cryo-compressor in 2015. The magnetic field at the Wiggler had to reduce from its normal operation field of 1.9 Tesla to 1.7 Tesla to maintain the operation of the storage ring and HXMA beamline during most time in 2016 due to one of the 4.2K cryo-cooler reaching its limit temperature. The cryogenic system was not reliable and became a risk of extended beamline shutdown. The operating cost of the HXMA wiggler had been very high due to frequent cryo-cooler failures and high liquid helium consumption level. Wiggler upgrades were installed in spring, 2017 including a replacement of the entire cryogenic system from Leybold to Sumitomo [3]. The associated components were also replaced by Budker Institute of Nuclear Physics (BINP) with a new design at cold fingers (gilded pins) and design modifications at the current lead assemblies, the shield cryo-cooler housings and the central throat assembly. The operation temperatures and pressure inside the wiggler cryostat have reduced dramatically after this replacement and modifications. There is no liquid helium consumption and the wiggler has been running at a higher magnetic field of 2.2 Tesla compared to the initial design specification of 2.0 Tesla since this upgrade. The HXMA beamline performance has improved in overall at operation reliability, stability, flex and beam quality.