Crab Cavities SPS cryogenics progress CCTC 05 June

Crab Cavities SPS cryogenics - progress CCTC 05 June 2013 Krzysztof Brodzinski 1

Contents • Cryogenics for Crab Cavities project – technical aspects and status • Circuits • Heat load • Capacity limitations with existing infrastructure + possible solutions • BA 4 work progress • 2 K pumping units test • Available space – integration • Cryogenics for SPS cryostat design • Process and instrumentation • Safety devices • Pumping collector sizing • Superfluid helium layer • Conclusions 2 K. Brodzinski - CCTC cryo_2013. 06. 05

Cryogenic circuits Regarding 2 K refrigeration Additional He source f Dra Buffer tank Service module t sio r e v n R EH TT LN 2 JT Screen PT Coupler intercept black –> existing 4. 5 K red –> to be constructed 2 K CC cryostat LT End cone intercept CC x 2 End cone intercept Screen EH TT 3 K. Brodzinski - CCTC cryo_2013. 06. 05

Heat loads and TCF 20 capacity V. Parma and colleagues The below values are calculated/estimated – no exact calculation is available yet depending on design) Equipment Heat load Source of capacity cryostat Static HL @ 2 K ~ 8 -10 W Dynamic @ 2 K ~ 5 -10 W HL @80 K ~40 -60 W TCF 20 -> 0. 4 -0. 5 g/s TCF 20/Buffer tank LN 2 Service module ~2. 5 W @ 2 K ~30 W @ 80 K TCF 20 -> 0. 13 g/s LN 2 Buffer tank* ~1. 5 W @ 4. 5 K ~ 19 W@ 80 K TCF 20 -> 0. 08 g/s LN 2 Transfer lines ~3. 4 W @ 4. 5 K ~26 W @ 80 K TCF 20 -> 0. 17 g/s LN 2 Flash at 2 K ~20% of liquefaction flow TCF 20 -> 0. 2 g/s Total net value: 0. 98 -1. 08 g/s Total with 1. 5 safety factor: ~1. 5 g/s 4 K. Brodzinski - CCTC cryo_2013. 06. 05

TCF 20 cold box capacity discussion Static heat load -> 0. 98 -1. 08 *1. 5 =~1. 5 g/s CERN isentropic equiv. recalculated with measured refrigeration capacity (120 W) CERN isentropic equiv. recalculated with guaranteed refrigeration capacity (85 W) CERN isentropic equiv. recalculated (20 l/h) Liquefaction capacity line [g/s] 0. 7 0. 85 1. 2 0. 76 1. 56 LEGNARO guaranteed liquefaction capacity (22 l/h) LEGNARO guaranteed liquefaction capacity with LN 2 (45 l/h) TCF 50 – 1. 74 g/s (recalculated from 50 l/h) Conclusions: • Existing TCF 20 without LN 2 boost is not sufficient to cover requirements (even upgraded as liquefier) • Plan B: Upgrade our TCF 20 as liquefier + install LN 2 boost (difficult because of safety and a lot of work – transfer lines to be installed, possible problems with instabilities of LN 2 flow – info from G. Passardi) • Plan C: Install upgraded “new” TCF 20 with LN 2 boost – liquefaction ~1. 7 l/h • Plan D: on the surface: Install a dewar 10000 L with link to 200 L buffer as a boost 5 K. Brodzinski - CCTC cryo_2013. 06. 05

Work done in BA 4 • • • • Inventory list, GMAO new naming definition list and PID update done by ~15. 09. 2012 All SVs re-qualified and installed – done by ~15. 09. 2012 Electrical motor and compressor maintenance – done by ~30. 09. 2012 Oil separation refurbished (coalescers cartridge replaced, ADS charcoal replaced) – done by ~30. 09. 2012 Storage – He tank re-qualified as pressure recipient – done on 12. 09. 2012 All other pressure recipients re-qualified – done by ~15. 10. 2012 Purging system on compressor station refurbished Cooling water and air ventilation installations for compressor station – refurbished Cold box vacuum system revised and partially refurbished Compressor station and cold box (partially) instrumentation revised Compressor station new electrical supply system with documentation done and tested by ~15. 11. 2012 Control system well advanced (partially ready) He tightness test done on compressor station First run of compressor station done by 30. 11. 2012 – milestone (OK operational, HP@6 bara) First helium flow through the cold box done on 18. 12. 2012 – milestone (OK, no leak into the vac) 6 K. Brodzinski - CCTC cryo_2013. 06. 05

Work done in BA 4 At SPS BA 4 there is a 4. 5 K cryogenic infrastructure used last time about 8 years ago for COLDEX experiment. It is foreseen to test its capacity and upgrade it for 2 K refrigeration – refurbishment is underway Renovated compressor + elec. motor – run test done Revised, labeled and qualified pressure control system / oil removal system Cold box TCF 20 New power supply panel for compressor station SPS LS 1 time frames: Open Access : 25/03/13 Close Access : 27/06/14 2 K pumping groups recovered from AMS TCF 20 Cold box 7 K. Brodzinski - CCTC cryo_2013. 06. 05

2 K pumping units performance test Both pumps were run to check their capacity – probably 2 pumps will have to be integrated in the tunnel – analysis underway. 8 K. Brodzinski - CCTC cryo_2013. 06. 05

Cryo integration in SPS Pump heater Buffer SM TCF 20 al rt ic ent ec m El uip eq Very tight integration if going behind the beam line (preferable because of distances to the client and free space in access gallery). 9 K. Brodzinski - CCTC cryo_2013. 06. 05

Tentative SPS CC cryogenic schedule Work planned for 2013: - Specification of cryogenics for CC testing to be written by end of January 2013 – decision comes from Fermilab meeting in Dec. 2012 - 2 K pumping group to be transported and integrated in the SPS tunnel in May/June 2013 – probably AMS groups could be adapted - Low pressure He recovery heating system to be transported and integrated in the SPS tunnel in May/June 2013 – probably AMS elements could be adapted - Electrical and control systems for 2 K cryogenics to be done (cables pulling included) – underway - Refurbishment of the cold box 4. 5 K – vacuum system and turbine circuits – done - Cold box control system to be completed – done - Cold box instrumentation revision/update to be completed – underway - Cold run of the cold box – by end of May 2013 – milestone – almost ready, conditioning underway - Liquefaction test of 4. 5 K cold box (potentially with boost at 80 K stage, if yes, this boosting system is to be developed and bought/constructed), some hardware modifications are required as preparation for this test – to be done by 15. 06. 2013 – milestone - Refurbishment of the supply/recovery system between BA 4 and North Area is to be done or procurement of additional buffer tank to fulfil requirements of helium availability for CC testing – to be analysed and confirmed – spring/autumn 2013 – milestone - LN 2 system for cooling of screen circuits to be developed and bought – to be confirmed - Buffer tank to be designed and bought - 2 K cryogenics: transfer line system to be designed and ordered (installation end of 2013 or in 2014) - 2 K cryogenics: Service module to be designed and ordered (installation end of 2013 or in 2014) - Participation in cryostat design – underway Main task for 2013/2014 is transfer lines design, fabrication and installation 10 K. Brodzinski - CCTC cryo_2013. 06. 05

Process & instrumentation 1/2 The cryostat will house 2 crab cavities and will be operated at 2 K (saturated helium bath ~30 mbar). The design should be done in the way to minimize the static heat load at 2 K. It will be equipped with two circuits 2 K and 80 K. The main interface should be provided from the top with 4 main lines (LHe IN, GHe pumping, 80 K IN and 80 K OUT). - Proposed piping can cover nominal operation and transients (cool down and warm up), - Interface to the cryostat: internal pipes welded, external envelope bolted (allowing opening of the jacket by means of sliding it up or down). It is not decided yet if 80 K screening will be provided with He or LN 2 (technical and safety analysis is underway). Power couplers and Cold/Warm Transitions will be intercepted at 80 K, then outgoing gas will be directed to recovery line. cryostat interface H SK C ET thermal screen at ~80 K common pumping collector helium tank CWT crab cavity CWT Power coupler intercept 11 K. Brodzinski - CCTC cryo_2013. 06. 05

Process & instrumentation 2/2 The cryostat should be equipped with the following instrumentation: • Helium level measurement – each helium tank should be equipped with a level gauge allowing for helium level measurement from the bottom through the phase separator (LT x 2, each gauge should allow for helium level regulation in the phase separator collector), • Pressure measurement on the saturated helium bath is to be provided (PT x 1), • Temperature measurement on each cavity helium tank is to be provided, installed on the bottom of each helium tank (suggested CERNOX type transducer, TT x 2), • Electrical heaters of 50 W are to be installed on each helium tank (EH x 2) • Temperature measurement on 80 K screen line is to be provided (TT x 2 on inlet and outlet) • JT valve and sub-cooling HX are foreseen to be installed out of the cryostat • (instrumentation for 80 K intercept circuits – definition underway) All sub atmospheric instrumentation/safety devices with ambient air interface will have to be equipped with appropriated helium guard. cryostat interface CH T KE TT S TT thermal screen at ~80 K LT PT LT common pumping collector helium tank CWT crab cavity TT TT EH EH CWT Power coupler intercept 12 K. Brodzinski - CCTC cryo_2013. 06. 05

Safety devices Assembly of cavity with helium tank have to be designed to withstand pressure of at least 2. 6 bar (delta. P of 2. 6 bar) without plastic deformation at ambient temperature. Design pressure for the cryostat assembly should be based on installed safety devices according to design rules (cryostat equipped with a safety valve set at 1. 8 bara* and a rupture disc set at 2. 2 bara*, possibly one device could be installed … - analysis underway) • both safety devices will be installed in the way to avoid potential projection of helium towards the passages or transport areas (deflectors installation to be analyzed, preliminary position for the rupture disc and safety valve have been proposed on transfer line close to the cryostat interface), • Both safety devices should protect the cavity and the cryostat from pressure rise causing plastic deformations, • Both safety devices should be equipped with appropriate helium guards. • The preliminary sizing of the devices is underway SV @ 1. 8 bara cryostat interface SK ET CH thermal screen at ~80 K common pumping collector Rupture disc @ 2. 2 bara helium tank CWT crab cavity CWT Power coupler intercept * Value compatible with recommendations given by T. Peterson on December 2012 Fermilab meeting 13 K. Brodzinski - CCTC cryo_2013. 06. 05

Pumping collector sizing Requirements: 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. Indications: Diameter of 100 mm (recommended) allows for: - return gas speed below 5 m/s up to ~90 mm of liquid level in the collector (operation regulation level to be set at ~50 mm of LHe in the collector), - buffer volume for transients/unexpected process perturbations (half filled collector allows for ~20 -30 min of operation assuming collector length of ~1. 6 m and 20 W of thermal load), - compatibility with safety valves sizing is still to be checked ! * Value compatible with recommendations given by T. Peterson on December 2012 Fermilab meeting He gas speed [m/s] Pumping collector gas speed * Liquid level 8. 00 7. 00 6. 00 5. 00 4. 00 3. 00 2. 00 1. 00 0 20 40 60 80 Level of liquid in the double phase line [mm] maxi: 5 m/s Regulation 100 mm ~90 mm ~50 mm 120 92 * Calculation done assuming: collector diameter of 100 mm, He mass flow = 2 g/s, GHe temp = 2 K, GHe press = 20 mbar. 14 K. Brodzinski - CCTC cryo_2013. 06. 05

Superfluid Helium layer Requirements: superfluid helium layer must cover whole surface of the cavity and provide correct operation of the cavity at required conditions (2 K). The heat transfer capability for superfluid helium layer have to be evaluated, typically between 0. 95 - 1 W/cm 2 Indications: assuming round cavity from below sketch; dimensions D=175 mm x L=700 mm and heat load of 20 W, the required minimum superfluid helium layer is ~ 2. 5 mm. From technology point of view this layer is recommended to be doubled to get min. 5 mm. It should not be enlarged without the limits in order to minimize reasonably the liquid helium volume (max. 40 L/cavity if possible). cryostat interface G IN L A SC O N – Units: [mm] CH ET SK common pumping collector helium tank 180 185 ~300 crab cavity 700 710 15 K. Brodzinski - CCTC cryo_2013. 06. 05

Conclusions • Work progressing well, cold box prepared for cold run in coming days, • The corresponding P&I diagram should be finalized in coming weeks, • 2 K pumping units – capacity test done -> 2 units to be integrated in the tunnel, • Cryostat design - close collaboration with regular working sessions is needed to merge between CERN requirements and the LARP design review, • Still a lot of work on infrastructure to fulfill requirements -> LN 2 line to be installed, probably He line to be installed through the shaft. 16 K. Brodzinski - CCTC cryo_2013. 06. 05