Chapter 6 - Performance of a cryogenic system for the superconducting RF cavity at NSRRC

Abstract

This chapter presents the performance and the features achieved by a helium cryogenic system that is designed based on the modified Claude cycle and provides cooling power to the superconducting RF cavity and the superconducting magnet in the synchrotron light source. Several events interrupt the operation of the cryogenic system. The oxygen sensor fails due to some unknown reason. Failure of the compressor motor is believed to have been caused from the poor lubrication of motor bearing. Failure of the output control card of the frequency driver may be owing to the overheating of its cabinet inside temperature. Damage of the warm turbine may be caused from impurity or dust. A poorly controlled cooling water temperature for the compressor leads to an oscillating helium temperature in the discharge line. A maximum cooling capacity of 469 W and a maximum liquefaction rate of 139 L/h is obtained at the storage dewar. Commission with the magnet is successful and shows small impact on the cryogenic system as coil quenches.