Simulation and Optimization of Helium Pressure Sensitivity Coefficient in the HWR019 Superconducting Cavity

The superconducting linac section of the China Accelerator Driven Transmutation Research facility (CiADS) operates in continuous wave (CW) mode, and the deformation and detuning of the superconducting cavity caused by the fluctuation of 4 K liquid helium pressure is an important factor affecting the stable operation of the low β cavity. Aiming at the problem that the half-wave superconducting resonant is affected by helium pressure fluctuations and the operation is unstable, and taking the half-wave superconducting resonant with an optimal beta of 0.19 (HWR019) in CiADS superconducting linac section as an example, the fluctuation of liquid helium pressure and the frequency change of the cavity are simulated by numerical simulation. The relationship between the liquid helium contact area of the cavity, the wall thickness of the cavity, the shape of the liquid helium cooling channel and the helium pressure sensitivity coefficient (K_Prees) of the cavity is calculated and analyzed, and the K_Press value of the superconducting cavity of HWR019 is reduced to close to 0. At the same time, through the thermodynamic calculation of the cavity, the corresponding enhanced heat transfer scheme is provided, which effectively reduces the maximum temperature of the superconducting cavity during operation, and ensures the demand for the stable operation of the low β superconducting cavity in CiADS.