Upgrading and experiment of the 6T superconducting Wiggler magnets' cryogenic system

Abstract

Abstract In 1998, the Hefei National Synchrotron Radiation Laboratory completed the 6T superconducting Wiggler magnets system. The consumption of liquid helium increases year by year during long operations. In order to upgrade the cryogenic system and realize zero volatilization of liquid helium, the GM cryocoolers are introduced as the cooling source. The liquid nitrogen and radiation-proof cold screen of the original cryogenic system were cancelled, and the original copper current lead was upgraded and replaced with the high-temperature superconducting current lead component. The cryogenic system's required cooling capacity is 2.33 W at 4.2 K and 108 W at 60 K. The system then selects three GM cryocoolers as the cryogenic source, which can provide 3.75 W at 4.2 K and 210 W at 60 K. In the absence of an external precooling source, the final cryogenic system successfully cooled and produced liquid helium at a liquefaction rate of 12 L/day at 1.1 bar (inflationary pressure) and had an excess cooling capacity of more than 1.05 W at 4.1 K.