Abstract:
Background Shenzhen Superconducting Soft X-Ray Free Electron Laser (S3FEL) is a facility newly proposed by Institute of Advanced Science Facilities, Shenzhen (IASF). The linear accelerator based on a TESLA-type superconducting RF cavity is used to obtain a high-repetition-frequency and high-gradient field. The cryomodule is the most challenging core part of the S3FEL device and ultra-high vacuum differential system is located at the module beam pipe outlet, which is used to realize the transition from cryomodule to ambient temperature section. The vacuum interlock protection is required for the differential system to protect the superconducting RF cavity in cryomodule from emergencies.
Purpose This study aims to analyze the transient process of rapid protection.
Method The traditional fast closing valve protection process is only calculated according to the gas molecular rate. In this paper, the finite element method and the Monte Carlo method are used in this paper.
Result The transient pressure distribution results of sensor-fast closing valve section show that setting the sensor 8—10 m away from the fast closing valve can provide sufficient buffer reaction time.
Conclusions The differential system analyses show that the pressure here reaches 10−5 Pa within 2 s when the gate valve is completely closed, corresponding to a leakage size of 0.5 mm, which still maintains a high-vacuum environment and meets the working requirements of ion pumps. This work provides an important theoretical basis for the S3FEL.
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