Research on cold helium automatic cooling scheme of 650 MHz double-cell superconducting cavity

In this paper, the cooling process of the 650 MHz double-cell superconducting cavity in Platform of Advanced Photon Source Technology R and D (PAPS) was taken as the main research object. The integral heat transfer model was constructed by using the criterion relation method and computational fluid dynamics (CFD) method, and the pre-inlet parameters of cold helium for superconducting cavity in the cooling process were obtained by programming calculation. According to the back-stepping process of the pre-inlet parameters, the relation between the opening percent of the temperature-changing valve and the pre-inlet parameters was calculated with full consideration of the overall layout and local resistance loss. The automatic control of the whole cooling process can be realized by the timetable of the opening percent of the temperature-changing valve. (authors)