Vladislav Benda ( CERN ), Klaus Barth ( CERN )

1. Internal review of superconductors and magnet laboratories2nd part: SM 18 & b.163: current status, weak points, possible improvement Cryogenics Vladislav Benda (CERN), Klaus Barth (CERN)

2. SM 18 operational diagram Review of cryo laboratories

3. SM 18 equipment 1/2 Review of cryo laboratories

4. SM 18 equipment 2/2 Review of cryo laboratories

5. GHe Combined cryogenic line (CCL) Cold compressor unit (CCU) LHe GHe pumping Very low pressure heater (VLPH) Cooling/warming line (CWL) Cooling line Returns Warming line GHe LHe Cryogenic line (CL) Cooling unit (CWU) & GHe heater Cryogenic feeder units (CFB) Magnet test facility in SM 18Heavy cold mass, frequent cool down/warm up, working at 1.8 K Review of cryo laboratories

6. GHe/LN pre-cooling system in SM 18 • Is it necessary to pre-cool cold masses with GHe/LN system? It is simpler to cool it down directly with LHe! • Consumption of LHe in litres required to cool down 1 kg of stainless steel • 1 – 32 from 300K to 4K • 0.1 – 1.4 from 80K to 4K • Maximum represent utilization only of a latent heat of LHe • Minimum represent a full enthalpy • Real figures depends on heat exchange during a cool down • It is evident that for heavy cold masses frequently cool down the GHe/LN pre-cooling system is more economic. Review of cryo laboratories

7. SRF cavity – LHe distribution line to be changed Heat leak to be reduced from ~12g/s to ~2 g/s (shielded line) 1.8 K pumping head to be integrated Total cost estimation ~ 800 kCHF All other cryogenic lines shall be low consumption, shielded lines. Full flow dryer and full flow precooler/adsorber to be installed Downtime reduction by avoiding the clogging The whole system can work permanently at full power (both 1.9 K pumping units). Cost estimation ~ 800 kCHF (French special contribution?) Upgrade of 6 kW cold box from refrigerator to liquefier 4 turbines to be changed/arranged including pipework Estimated extra LHe production ~ 4 g/s Cost estimation ~ 500 kCHF Control system from ABB & PCview32 to UNICOS Duration: 2 years Budged required: ~250 kCHF Resources required: 1 engineer for 2 years Implementation by steps Stop for 2-3 weeks Proposal of SM 18 cryogenic upgrade Review of cryo laboratories

8. Design and Technical specification to be done One valve box required per a bench Particularity of the line Twin valve protection Bench branch lines disconnected while the main line is cold He guard Protection of sub-atmospheric circuits Protection of twin valves volume Each valve box includes: One heat exchanger One phase separator One He guard Proposal of the new cavity cryogenic distribution line in SM 18 Review of cryo laboratories

9. Proposal of the new full low purifier in SM 18 Full flow helium dryer Full flow precooler/adsorber unit Review of cryo laboratories

10. Number of Tests in SM18 up to 2014 Review of cryo laboratories

11. Compatibility with 6 kW (@ 25 g/s) CB LHe production Average consumption needed (in g/s) • Considering 6 kW CB current capacity 25 g/s, the requirements cannot be fulfilled at a present condition. • Only if the CB is fully upgraded (~30g/s) and the cavity transfer line is changed the requirement can be fulfilled except for 2013. • Peak of consumption possible: boosting by LHe, GHe to atmosphere or adapting the priorities between the tests. • New cavity line and CB upgrade is not expected before 2011. * Estimated consumption of the new line ~2g/s ** Consumption of the existing line ~12 g/s Review of cryo laboratories

12. SM 18 summary • Compatibility of LHe required consumption and LHe production • Reduction of LHe consumption • New distribution SRF cavity cryogenic distribution line • All other cryogenic lines, cryostats and valve boxes to be shielded • Increase of cooling capability • 6 kW cold box upgrade • In any case the consumption requirement in 2013 cannot be fulfilled • Control system to be transferred to Unicos • Typical tests suitable for SM 18 • Heavy cold masses to be pre-cooled by GHe/LN circulation preferable at high pressure • Working temperature 1.8 K Review of cryo laboratories

13. Building 163 operational diagram Review of cryo laboratories

14. Building 163 equipment 1/2 Review of cryo laboratories

15. Building 163 equipment 2/2 Review of cryo laboratories

16. Liquefaction capacity in b.163 • Nominal capacity 150 l/h • Real capacity 130 l/h ~5g/s • Today capacity 80 l/h • because of turbine filter clogging (charcoal powder?) • Change of the filter is foreseen for week 28 • Stop for 3 weeks, Unicos transfer in the same time • Cost estimation10 kCHF • Required capacity 130 l/h • Possibility to boost capacity by external source of LHe • Limitation: volume of He buffers • Possibility to use BEBC buffers more efficiently. New connecting line of a larger diameter is required. • At a peak consumption GHe possibly to atmosphere Review of cryo laboratories

17. Building 163 summary • Major part of the equipment is in a good condition • Weak point to be treated • 1.8 K Freska pumping unit is too old • Its replacement is recommended • Cold box • Clogging of the filter to be investigated and solved • If more often replacement of the filter is required an access shall be improved. • Quite old • Possibility to change it for Block 4 cold box • 6 “BEBC” buffers to be use more efficiently Review of cryo laboratories

18. HP recovery Burckhardt compressors in SM 18 Review of cryo laboratories

19. 1.8K Fresca pumping unit Review of cryo laboratories