Design of helium thermo-siphon circuit for injector cryomodule of superconducting electron linac

Design of a ICM for VECC's superconducting electron linac project based on the technology developed for niobium made elliptical TESLA type SRF cavities is underway in collaboration with TRIUMF. There are five connections to a single cavity, operating at 2K temperature, from atmosphere in the form of two beam tubes, two couplers and a tuner. Penetrations were intercepted at 77K temperature and 4K temperature to reduce the heat leak to the cavity.

Thermo-siphon loops are designed to minimize the heat load to the 2K cavities. Analytical analysis is carried out to estimate the effect of heat load on the helium flow rate through the loops using diameter of the tube as parameter. Effect of the inclination of the thermosiphon's hot arm were studied and accordingly thermo-siphon loops were optimized within the physical constrain of the ICM. Temperature rise at the cavity beam tube flanges were estimated to facilitated the desired heat removal.