The vacuum group is primarily responsible for the operation, maintenance, and upgrade of the vacuum system for the Heavy Ion Research Facility in Lanzhou-Cooling Storage Ring (HIRFL-CSR), as well as the development of vacuum systems for newly constructed accelerators. The team currently consists of 23 researchers, including 2 chief engineers and 10 senior engineers, with eight members holding doctoral degrees or are currently pursuing doctoral degrees.

The team focuses on frontier technologies in accelerator development and is dedicated to research on extreme/ultra-high vacuum(XHV/UHV) generation techniques. This research encompasses multiple areas including advanced XHV/UHV technology, surface modification of materials, advanced vacuum instrument R&D, dynamic vacuum suppression, development of a low-eddy-current XHV/UHV chamber, and cryogenic XHV systems.

The team has successfully completed the construction of vacuum systems for multiple major scientific projects, including the HIRFL-CSR, the Heavy Ion Medical Machine (HIMM), the Space Environment Simulation and Research Infrastructure (SESRI), and the Proton Radiation Effects Facility (PREF), which are all large-scale XHV/UHV systems. Among them, the PREF was awarded the Special Prize for Technological Invention by the Chinese Nuclear Society, while SESRI was awarded the First Prize for Scientific and Technological Progress in Gansu Province.

The UHV/XHV system for the new generation High intensity heavy ion Accelerator Facility (HIAF), constructed by the vacuum group, has passed the subsystem acceptance. Notably, the average vacuum in its Booster Ring (BRing) is better than 5×10^-10 Pa, reaching the highest level of similar accelerators internationally. Driven by the needs of large-scale scientific facility construction and oriented toward breaking through critical technologies, the team has overcome a series of key technical challenges. Their efforts have laid a technical foundation for the successful commissioning of HIAF and its multiple world-record achievements in beam intensity. A new scheme for ultra-thin-walled XHV chambers with an internal lining skeleton based on "3D printing + NEG coating" has been proposed, and it has been successfully applied to the HIAF-BRing, establishing the world's largest ultra-thin-walled XHV system at room temperature. The developed split-type inflatable expansion flange has been successfully applied to automated remote maintenance in the high-radiation area.

After years of accumulation and development, the vacuum group has fully mastered the key process and technical routes for achieving UHV/XHV, and possesses the capability of independently designing and constructing UHV/XHV systems.This provides a technical foundation for the construction of vacuum systems in subsequent projects such as new heavy ion therapy facility, ultra fast ramping accelerator facility, and Suzhou medium and high-energy heavy ion accelerator facility.

Advanced Extreme/Ultra-High Vacuum(XHV/UHV) Technology

Surface Modification of Materials

Adcanced Vacuum Instrument R&D

Dynamic Vacuum Suppression

Development of a Low-Eddy-Current XHV/UHV Chamber

Cryogenic XHV Syste

Publications：

1. J. Meng, C. Luo, Z. Chai, et al. Use of combined sputter ion and NEG pumps in the heavy ion medical machine. Vacuum. 114(2015)108-113.

2. C. Luo, J. Meng, J.C. Yang, et al. Study on the performance of titanium alloy-lined thin-walled vacuum chamber. Vacuum. 221(2024)112808.

3. W. J. Xie, J. Meng*, J. L. Liu, et al. Mechanical performance evaluation and structural optimization of ceramic lined thin-walled vacuum chambers. Vacuum. 217(2023)112540.

4. J. Q. Jiao, J. Meng*, C. C. Li, et al. The vacuum characteristics of Ti-Zr-V and Ti film coatings on titanium alloy-lined thin-wall chambers at low temperatures. Vacuum. 245(2025)114985.

5. C. C. Li, C. Luo, J. L. Liu, et al. Study on Au coating of ceramic-lined thin-wall vacuum chamber for HIAF. Vacuum. 184(2021)109898.

6. W. J. Xie, J. Meng*, C. C. Li, et al. Measurement on the Desorption Yields of Ceramic and Au-coated Ceramic irradiated with Bi³²⁺ and Xe²³⁺. Vacuum. 194(2021)110636.

7. J. Q. Jiao, J. Meng*, W. J. Xie, et al. The effect of eddy current in a titanium alloy-lined thin-wall chamber on vacuum characteristics and study of cooling methods. Vacuum. 245(2025)114960.

8. W. J. Xie, J. Meng,Y.S. Yang, et al. Multi-objective optimization of ceramic-lined thin-walled vacuum chamber based on response surface method. Nuclear Inst.and Methods in Physics Research, B.569(2025)165915.

9. Z. Chai, N. F.Wei, J.Q.Jiao, et al. Study on baking deformation of the thin-walled arc chamber. Vacuum. 210(2023)111856.

10. C. Luo, P. Li, W. J. Xie, et al. Application of compact Non-Evaporable Getter and Sputter Ion Pump combination in UHV system of HIAF. Vacuum. 157(2018)159-165.

Patents：

1. Method for manufacturing ultra-thin-wall vacuum chamber with reinforcement rib structure, China Patent CN117066822B.

2. TiZrCo vacuum getter film and preparation method and application, China Patent CN116575005B.

3. TiZrV-Al magnetron sputtering target material and preparation method, China Patent CN116555714B.

4. Method for manufacturing titanium alloy thin-wall reinforcement rib ultra-high vacuum chamber, China Patent CN115921899B.

5. Method for manufacturing titanium alloy thin-wall reinforcement rib ultra-high vacuum chamber, China Patent CN115921899B.

6. Multi-target DC magnetron sputtering coating device and its application in depositing multi-layer metal films on ceramic substrates, China Patent CN115386848B.

7. Desorption rate testing device for vacuum system, China Patent CN111398405B.

8. Manufacturing method for large-size curved ultra-high vacuum chamber, China Patent CN120663073B.

9. Integrated ultra-high vacuum pipeline pump for particle accelerators, China Patent CN119933982B.

10. Manufacturing method for cryogenic getter pump, China Patent CN118669296B.

11. Manufacturing method for ultra-thin-wall metal-lined vacuum chamber, China Patent CN116133225B.

12. Vacuum chamber structure with ultra-thin wall and metal lining, China Patent CN116489863B.

13. Curved accelerator inner wall coating device and magnetron sputtering coating method, China Patent CN111334770B.

14. A strength testing device for accelerator vacuum pipelines, China Patent CN111504792B.

15. A process for reducing the outgassing rate of ferrite surfaces, China Patent CN119676930B.