1. CSNS cryogenic system Institute of High Energy Physics Guoping Wang (wanggp@ihep.ac.cn) June 21, 2016

2. 散裂中子源进展汇报 June 21, 2016 Contents Introduction of CSNS cryogenic system Engineering progress of CSNS cryogenic system Summary

3. 散裂中子源进展汇报 June 21, 2016 3 CSNS Overview CSNS is designed to accelerate proton beam pulses to 1.6 GeV kinetic energy at 25 Hz repetition rate, striking a solid metal target to produce spallation neutrons. The accelerator is designed to deliver a beam power of 100 kW. Aerial photo, 2015-11-17

4. 散裂中子源进展汇报 June 21, 2016 4 Requirements of CSNS cryogenic system  CSNS cryogenic system provides hydrogen to keep the two moderators at 20K.  Dynamic heat load: DM: 400W (25% margin) CM: 300W (25% margin)

5. 散裂中子源进展汇报 June 21, 2016 CSNS cryogenic system Mission of CSNS cryogenic system: Provide 20 K cryogenic hydrogen to moderator; Temperature difference is lower than 3 K between the entrance and exit of hydrogen moderator; Concentration of para-hydrogen is higher than 99%. Safety, reliable, and stable operation of cryogenic system.

6. 散裂中子源进展汇报 June 21, 2016 Layout of CSNS cryogenic system Compressor roomGas room Hydrogen room Refrigerator room Tank area Target stationHydrogen cryogenic transfer lines

7. 散裂中子源进展汇报 June 21, 2016 CSNS cryogenic system Flowchart of CSNS cryogenic system

8. 散裂中子源进展汇报 June 21, 2016 Helium refrigerator, 2200 W@20 K, purchased from Linde, has arrived at CSNS cite. Acceptance test will be performed in June 2016. Compressor Purifier/Absorber Helium cold box and the control cabinet

9. 散裂中子源进展汇报 June 21, 2016 Key equipment in hydrogen loop: Two hydrogen circulators One hydrogen-helium heat exchanger One hydrogen heater One ortho-para hydrogen convertor One accumulator All equipment have been purchased or developed in 2015. Hydrogen circulator Hydrogen-helium heat exchanger Hydrogen heater and O-P convertor Accumulator

10. 散裂中子源进展汇报 June 21, 2016 Hydrogen cold boxAccumulator cold box Cryogenic hydrogen system adopted Double cold boxes: one hydrogen cold box one accumulator cold box In one case, the accumulator breaks out, it will be much more convenient to remove and replace.

11. 散裂中子源进展汇报 June 21, 2016 Complete assembly of hydrogen cold box and accumulator cold box in 2015. Hydrogen cold boxAccumulator cold box

12. 散裂中子源进展汇报 June 21, 2016 Engineering progress Hydraulic test of cryogenic hydrogen circulator Tested with 120 K cryogenic nitrogen gas Design parametersValue Working pressure1.5 MPa Inlet temperature20 K Flow rate1 l/s Pressure head0.1 MPa

13. 散裂中子源进展汇报 June 21, 2016 Cooling test of hydrogen cold box Filling liquid nitrogen in the helium-side, and use helium instead of hydrogen in the hydrogen loop. Within 2 hours, maximum temperature in hydrogen cold box cooled down to 90 K. Cool down processMan-machine interface

14. 散裂中子源进展汇报 June 21, 2016 Cooling test of accumulator cold box Filling liquid nitrogen in the hydrogen-side, and simulate the pressure fluctuation by helium gas. Connect helium gas cylinders in the helium-side, to provide stable back pressure (1.5 MPa).

15. 散裂中子源进展汇报 June 21, 2016 Cryogenic transfer lines 1. Two double-channel cryogenic hydrogen transfer lines, 40 meters per one. 2. Six single-channel cryogenic hydrogen transfer lines 3. Two single-channel cryogenic helium transfer lines Layout of cryogenic transfer lines Sectional view of double-channel cryogenic transfer lines

16. 散裂中子源进展汇报 June 21, 2016 Cryogenic transfer lines 1. Completed prefabricate sections of cryogenic transfer lines. 2. Installed 12 m vertical part in January 2016. Interface of cryogenic transfer lines between cryogenic system and moderator Vertical part of cryogenic transfer lines

17. 散裂中子源进展汇报 June 21, 2016 Summary Acceptance test of helium refrigerator in June 2016. Commissioning of cryogenic system in the end of 2016. Joint commissioning with moderator system. This year Manufactured hydrogen cold box and accumulator cold box. Successful tested hydrogen cold box and the accumulator cold box with liquid nitrogen. Finished structural design and prefabricated sections of cryogenic transfer. Present

18. Thank you ！