ADS Injector-I 2 K superfluid helium cryogenic system

The Accelerator Driven Sub-critical (ADS) system is a strategic plan to solve the nuclear waste problem for nuclear power plants in China. High-energy particle accelerators and colliders contain long strings of superconducting devices, superconducting radio frequency cavities, and magnets, which may require cooling by 2 K superfluid helium (Helium II). 2 K superfluid helium cryogenic system has become a research hot spot in the field of superconducting accelerators. In this study, the ADS Injector-I 2 K cryogenic system is examined in detail. The cryogenic system scheme design, key equipment, and technology design, such as the 2 K Joule–Thomson (J–T) heat exchanger and cryomodules CM1 + CM2 design, are examined, in addition to the commissioning and operation of the cryogenic system. The ADS Injector-I 2 K cryogenic system is the first 100 W superfluid helium system designed and built independently in China. The ADS proton beam reached 10 MeV at 10 mA in July 2016 and 10 MeV at 2 mA in continuous mode in January 2017 and has been operated reliably for over 15,000 h, proving that the design of ADS Injector-I 2 K cryogenic system, the key equipment, and technology research are reasonable, reliable, and meet the requirements. The research into key technologies provides valuable engineering experience that can be helpful for future projects such as CI-ADS (China Initiative Accelerator-Driven System), SHINE (Shanghai High Repetition Rate XFEL and Extreme Light Facility), PAPS (Platform of Advanced Photon Source Technology), and CEPC (Circular Electron-Positron Collider), thereby developing national expertise in the field of superfluid helium cryogenic systems.