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CERN Cryomodule Requirements for Crab C avities

CERN Cryomodule Requirements for Crab C avities. O. Capatina (CERN). Functional specification. https ://espace.cern.ch/HiLumi/WP4/Lists/Team%20Discussion/AllItems.aspx. General. SPS tests LHC final configuration. General. LHC environment. Q4. D2. IP. D2. Q4. General.

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CERN Cryomodule Requirements for Crab C avities

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  1. CERN Cryomodule Requirements for Crab Cavities O. Capatina (CERN) LHC Crab Cryomodule meeting

  2. Functional specification https://espace.cern.ch/HiLumi/WP4/Lists/Team%20Discussion/AllItems.aspx LHC Crab Cryomodule meeting

  3. General • SPS tests • LHC final configuration LHC Crab Cryomodule meeting

  4. General • LHC environment LHC Crab Cryomodule meeting

  5. Q4 D2 IP D2 Q4 General • LHC environment • ~ 10m LHC Crab Cryomodule meeting

  6. General • LHC environment LHC Crab Cryomodule meeting

  7. General • SPS environment LHC Crab Cryomodule meeting

  8. General • SPS environment LHC Crab Cryomodule meeting

  9. General • SPS : • 2 (identical) cavities in a cryomodule • 3 different cryomodules LHC Crab Cryomodule meeting

  10. General • SPS : • 2 (identical) cavities in a cryomodule • 3 different cryomodules LHC Crab Cryomodule meeting

  11. General • SPS : • 2 (identical) cavities in a cryomodule • 3 different cryomodules LHC Crab Cryomodule meeting

  12. Geometrical constraints • SPS : LHC Crab Cryomodule meeting

  13. Geometrical constraints • SPS : LHC Crab Cryomodule meeting

  14. Geometrical constraints • SPS : LHC Crab Cryomodule meeting

  15. Geometrical constraints • SPS dummy beam pipe : SPS configuration LHC configuration LHC Crab Cryomodule meeting

  16. Geometrical constraints • SPS - dummy beam pipe : • Dummy LHC beam pipe at 194mm horizontally from the SPS beam pipe • Dummy beam pipe can be on either side of the cavity but preference opposite to Y chamber LHC Crab Cryomodule meeting

  17. Geometrical constraints • SPS - dummy beam pipe : • Dummy LHC beam pipe at 194mm horizontally from the SPS beam pipe • Dummy beam pipe can be on either side of the cavity but preference opposite to Y chamber LHC Crab Cryomodule meeting

  18. Geometrical constraints • SPS - dummy beam pipe : • Dummy LHC beam pipe at 194mm horizontally from the SPS beam pipe • Dummy beam pipe can be on either side of the cavity but preference opposite to Y chamber LHC Crab Cryomodule meeting

  19. Geometrical constraints • SPS – Y chamber apperture: • With new Y chamber (510 mm aperture), SPS cryomodule transverse dimensions coherent to LHC => could allow similar SPS/LHC basic solutions for tuner, coupler position • SPS cryomodule design should not be over-constrained • Baseline: replacing the existing SPS Y chamber LHC Crab Cryomodule meeting

  20. Geometrical constraints • SPS interfaces: • Connexions to main coupler • From top, vertically LHC Crab Cryomodule meeting

  21. Geometrical constraints • SPS interfaces: • Connexions to main coupler • Limit risk of loads transmitted directly to the cavity from connection to RF module – Double walled tube could be used as part of the supporting system of the cavity LHC Crab Cryomodule meeting

  22. Geometrical constraints • SPS interfaces: • Connection to cryo • From top, vertically for main circuits • N2 warm return may be sidewise cryostat interface thermal screen at ~80 K common pumping collector helium tank CWT crab cavity CWT Power coupler intercept LHC Crab Cryomodule meeting

  23. Alignment • LHC - Alignment requirements (position accuracy and position stability) – based on general beam dynamics considerations: • Transverse rotation per cavity should be less than 5 mrad • Transverse misalignment per cavity (in both planes) should be less than 0.7 mm • Cavity tilt with respect to the longitudinal axis should be less than 1 mrad • Cavity longitudinal misalignment should be less than 10 mm • Active alignment will be studied in a dedicated set-up LHC Crab Cryomodule meeting

  24. Alignment • SPS • Alignment required for operation less than LHC • To limit SPS crymodule complexity (win time and limit risk) • No active alignment needed for SPS tests • Foresee a system for monitoring the cavity positions instead LHC Crab Cryomodule meeting

  25. Process & instrumentation • Operated at 2 K saturated helium bath -> ~30 mbar • Two circuits: 2 K and 80 K • Main interface from the top with 4 main lines (LHe IN, GHe pumping, 80 K IN and 80 K OUT): • internal pipes welded, external envelope bolted cryostat interface thermal screen at ~80 K common pumping collector helium tank CWT crab cavity CWT Power coupler intercept See Krzysztof’s talk LHC Crab Cryomodule meeting

  26. Process & instrumentation • 80 K screening will be provided with He or LN2 • Power couplers and Cold/Warm Transitions intercepts at 80 K, then outgoing gas directed to recovery line cryostat interface thermal screen at ~80 K common pumping collector helium tank CWT crab cavity CWT Power coupler intercept LHC Crab Cryomodule meeting

  27. Process & instrumentation • In general: maximize instrumentation for the prototypes • Minimum instrumentation requirements: • Gauge for helium level measurement from the bottom through the phase separator to be installed for each helium tank (LT x 2) • Pressure measurement on the saturated helium bath (PT x 1) • Temperature measurement on the bottom each helium tank (suggested CERNOX type transducer, TT x 2) • Electrical heaters of 50 W on each helium tank (EH x 2) cryostat interface thermal screen at ~80 K common pumping collector helium tank CWT crab cavity SKETCH CWT Power coupler intercept EH EH PT TT TT LT LT LHC Crab Cryomodule meeting

  28. Process & instrumentation • Temperature measurement on 80 K screen line (TT x 2 on inlet and outlet) • Instrumentation for 80 K intercept circuits – definition underway • JT valve and sub-cooling HX are foreseen to be installed out of the cryostat • All sub atmospheric instrumentation/safety devices with ambient air interface will have to be equipped with appropriated helium guard. cryostat interface thermal screen at ~80 K common pumping collector helium tank CWT crab cavity SKETCH CWT Power coupler intercept EH EH PT TT TT LT LT LHC Crab Cryomodule meeting

  29. Piping sizing • Pumping collector sizing (recommended 100mm dia) • Gas speed lower than 5 m/s • Min 50 mm for level regulation, additional buffer for ~ 20 min of operation • Compatibility with safety devices for pressure limit requirements to be confirmed Liquid level 100 mm ~90 mm maxi: 5 m/s 92 Regulation ~50 mm 0 mm * Calculation done assuming: collector diameter of 100 mm, He mass flow = 2 g/s, GHe temp = 2 K, GHe press = 20 mbar. LHC Crab Cryomodule meeting

  30. Helium tank sizing • Helium tank to be dimensioned correctly to extract maximum heat load • Heat flux in He II depend on bath temp. and channel dimension LHC Crab Cryomodule meeting

  31. Helium tank sizing • Helium tank to be dimensioned correctly to extract maximum heat load • If helium cross section expected to extract (order of magnitude) 1 W/cm2 => detailed calculations needed • Minimize reasonably the liquid helium volume (max. 40 L/cavity if possible) LHC Crab Cryomodule meeting

  32. Heat load budget LHC Crab Cryomodule meeting

  33. Safety equipment • Given its designated function, we are in the presence of ‘high safety relevance’ equipment, i.e., special equipment according to CERN’s SR-M; • The HSE Unit Safety Commission shall give clearance from design’s release to commissioning; • A Safety File with all relevant technical documentation to be approved by the Safety Commission shall be prepared from day 1 (EDMS); See talk of Luis LHC Crab Cryomodule meeting

  34. Safety equipment • Two design strategies are possible: to EN Standards or to ASME Section VIII + specific technical requirements; • Combined design (EN+ASME) can be accepted if justified; • Design shall target the hydrostatic test pressure of 2.6 bar (abs, helium vessel); • Equivalent to EN conventional material grades are preferred; • ‘Non-conventional’ material properties are to be demonstrated by testing. LHC Crab Cryomodule meeting

  35. Materials • Helium tank material not imposed; however titanium involves • More complex interfaces • Not covered by the Harmonised European Standards • Stainless steel flanges (1.4429, AISI 316LN) for beam pipe interface • Equivalent to EN conventional material grades are preferred LHC Crab Cryomodule meeting

  36. Magnetic shielding • Static magnetic field shielding required • The field to be below 1 µT at the outer surface of the cavity • Numerical simulations to determine the material thickness and specification, as well as geometry LHC Crab Cryomodule meeting

  37. Cryostating • Integration into cryostat at CERN - most likely location SM18 LHC Crab Cryomodule meeting

  38. Concluding remark • SPS cryomodule: • Expected 3 different conceptual designs by the end of the year • Collaboration with regular working sessions to merge CERN requirements and LARP/UK effort • CERN is ready to help with several competencies LHC Crab Cryomodule meeting

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