Operation of cryogenic permanent magnet undulators for X-ray beamlines

Jui-Che Huang^1*, Ching-Sheng Hwang¹, Yu-Chun Chuang¹, Chih-Sheng Yang¹

¹Magnet Group, National Synchrotron Radiation Research Center, HsinChu City, Taiwan

* Presenter:Jui-Che Huang, email:huang.juiche@nsrrc.org.tw

A High-resolution powder X-ray diffraction beamline (BL19) is commissioning at Taiwan Photon Source (TPS). Since the spectral quality from cryogenic permanent magnet undulators (CPMUs) can be superior to that of in-vacuum undulators (IVUs), a PrFeB-based CPMU with a period length of 15 mm has been constructed to provide high brilliant X-rays. The magnets of the CPMU need to be cooled to 80 K to generate an effective magnetic field of 1.02 T at a gap of 5 mm. Two cryo-coolers, each with a cooling capacity of 220W at 80 K, allow a high beam-induced heat load with external heat transfer of up to a few hundred watts. However, beam-induced heatload is large at beam current of 500 mA ,so design of cryostat need more robust . The relevant results of operating and commissioning the TPS-CPMU will be presented.

Keywords: Undulator, Beam-induced heatload, Cryostat