1. Possible proposed designs Part II : designs comparison SPL power coupler 16/03/2010Eric Montesinos / CERN-BE-RF-SR

2. Summary  Comparison of proposed designs:  SPL-CEA coaxial disk water cooled window  SPL-SPS coaxial disk air cooled window  SPL-LHC cylindrical air cooled window  Design issues  Waveguides  Titanium coating  RF simulations  Coupling box  Construction process  Conditioning process  Mass production  New proposed schedule  Conclusion 16/03/2010 2 Eric Montesinos / CERN-BE-RF-SR

3. Three possible remaining designs 16/03/2010Eric Montesinos / CERN-BE-RF-SR 3  All use the same double walled tube  All use the same vacuum gauge, electron monitor and arc detector  We have designed them to be compatible without modifying the cryomodule

4. Three possible remaining designs 16/03/2010Eric Montesinos / CERN-BE-RF-SR 4  SPL-CEA HIPPI coaxial disk water cooled window  SPL-SPS coaxial disk air cooled window  SPL-LHC cylindrical air cooled window

5. Coaxial disk water cooled window  CEA design based on a coaxial disk ceramic window as in operation at KEKB and SNS, modified for 704MHz  Advantages  High power capability, tested up to 1MW with 2ms / 50Hz on warm test cavity and on cold cavity last week  Matched window, this allows to easily change the waveguide position  Commercially produced window (Toshiba)  Drawbacks  Window and antenna are water cooled: Not following CERN vacuum group recommendations Needs accurate mounting  Difficult DC HV biasing due to water: Need insulating pipes (X-rays, radiation,... More maintenance and operational costs)  Need a second air cooling circuit for the waveguide: Doubles the operational needs: water and air systems 16/03/2010 5 Eric Montesinos / CERN-BE-RF-SR Antenna and outer ceramic water cooling Waveguide air cooling

6. Coaxial disk water cooled window  Quite complex brazing process (compare to SPS and LHC)  Water seal to be modified from organic (acceptable for test) to metallic (for long term operation without maintenance)  the tolerances are very tight  No flexibility for the antenna:  Stress to the ceramic  RF contact depends on tolerances  Possible water leak if misalignment (already happened) 16/03/2010 6 Eric Montesinos / CERN-BE-RF-SR

7. Coaxial disk air cooled window  Design based on a coaxial disk ceramic window similar as the one in operation on the CERN SPS TWC 200MHz power load  Advantages  Very simple and well mastered brazing of ceramic onto a titanium flange  High power capability (500kw cw)  Very easy to cool with air  Waveguide as “plug and play” mounting, absolutely no stress to the antenna  DC HV biasing very simple, with again a “plug and play” capacitor fitting, and again no stress to the ceramic due to finger contact  Least expensive of the three couplers !  Minor drawback  Ceramic is part of the matching system, fixes the waveguide position 16/03/2010 7 Eric Montesinos / CERN-BE-RF-SR Antenna and outer ceramic air cooling Ceramic and waveguide air cooling

8. Coaxial disk air cooled window  Very simple brazing process:  Titanium outer flange: Dilatation coefficient near ceramic Surface hard enough for vacuum copper seals  Inner tube in copper 1.2mm thickness to allow easy brazing  Antenna inner upper part has been designed:  With spring washers for a good RF contact between the upper and lower inner conductor sections  Without any stress to the ceramic  Allowing a correct air flow 16/03/2010 8 Eric Montesinos / CERN-BE-RF-SR Spring washers RF contact SPS Window: very simple brazing process RF contact without stress to the ceramic by compression of the outer line through the air “cane” Air “cane”

9. “Plug and play” waveguide system  Need additional 50 Ω outer lines:  Vacuum side for monitoring vacuum, electron, light, …  Air side for RF matching and for air cooling of the ceramic  “Plug and play” waveguide and biasing capacitor  There is a finger contact all around the capacitor to avoid stress on the ceramic  This waveguide mounting method has already been used successfully for the LHC couplers 16/03/2010 9 Eric Montesinos / CERN-BE-RF-SR

10. Cylindrical air cooled window  Design based on the same cylindrical window as the LHC couplers:  Long and difficult process to achieve reliability of the window, the final design was obtained after more than six years of studies  As the design was complex, we keep it exactly as it is  Instead of changing the ceramic design we have adapted the line to the ceramic  Advantages  High power capability window, LHC proven (575kW cw full reflection, could be more…)  Simple to cool with air  Absolutely free of mechanical stress on the antenna  Same “plug and play” waveguide and DC capacitor as previous design, no stress to the ceramic  Simplest version to assemble !  Drawbacks  Ceramic is part of the matching system, fixes the waveguide position  Possible multipacting due to the outer conical outer line 16/03/2010 10 Eric Montesinos / CERN-BE-RF-SR Ceramic and waveguide air cooling

11. Cylindrical air cooled window  LHC window is a huge improvement over the LEP window, with less losses and higher power capability  We still not know the upper power limit of the LHC window  The LHC coupler were powered up to 575kW cw full reflection (SW) for several hours all phases  Klystrons failed, not the coupler !  The LHC window appears to be really robust  To date 30 LHC couplers have been built and tested, 16 are in operation in LHC  A new coupler using exactly the same ceramic window is under construction for ESRF and SOLEIL → Standardization of the ceramic 16/03/2010 11 Eric Montesinos / CERN-BE-RF-SR ESRF-LHC new design First EB welding (mechanical) Second EB welding (mechanical and vacuum) Third EB welding (mechanical and vacuum) LHC window: Two solid copper collars brazed to the ceramic

12. “Plug and play” waveguide system  Same “Plug and play” waveguide and biasing capacitor as with the coaxial air cooled window  The waveguide has just one contact with the body line  There is a finger contact all around the capacitor to avoid stress on the ceramic 16/03/2010 12 Eric Montesinos / CERN-BE-RF-SR

13. Comparison: Titanium coating  LHC, coating done twice:  First coating on the top and the bottom edges of the ceramic (electrical continuity)  Brazing of the copper collars  Second coating on the inside of the ceramic  → Double the costs  SPS, only one coating:  Straight forward  Done after brazing  Toshiba process:  Probably one coating  What about the part of ceramic masked by the chokes? 16/03/2010 13 Eric Montesinos / CERN-BE-RF-SR First coating: R = 0.5 M Ω Second coating: R = 2 M Ω One coating: R = 2 M Ω One coating: R = 2 M Ω What about the part of ceramic behind the choke ? ?

14. Comparison: S11 simulations Cavity bandwidth 704 MHz / Qext (1.2 x 10 6 ) = 586 Hz DesignCenter frequency [MHz] Bandwidth < - 25 dB [MHz] CEA702.825.2 LHC704.213.2 SPS704.426.2 16/03/2010 14 Eric Montesinos / CERN-BE-RF-SR SPL-CEA SPL-SPS SPL-LHC

15. Comparison: Field Strength 16/03/2010 15 Eric Montesinos / CERN-BE-RF-SR SPL-CEA SPL-LHC SPL-SPS Max 751 kV/m with 1MW Max 880 kV/m with 1MW Max 866 kV/m with 1MW Hodgman, Charles D. & Norbert A. Lange. Handbook of Chemistry and Physics 10th Edition. Cleveland, OH: Chemical Rubber Publishing Co, 1925: 547. "Spark length (cm),.10; Point electrodes, 3720; Ball electrodes, 1 cm diameter: Steady potential, 4560; Alternating potential, 4400" 3.7–4.5 MV/m Tipler, Paul A. College Physics. Worth, 1987: 467. "This phenomenon, which is called dielectric breakdown, occurs in air at an electric field strength of about E max = 3 × 10 6 V/m." 3.0 MV/m Rigden, John S. Macmillan Encyclopedia of Physics. Simon & Schuster, 1996: 353. Air; Dielectric Constant, 1; Strength E s (kV/mm), 3 3.0 MV/m Riley, Lewis A. Dielectrics. 1999-2000.Dielectrics "The dielectric strength of air is about 3 × 10 6 V/m" 3.0 MV/m

16. Waveguides options  If needed, LHC design could be done with a “coaxial conical” extension line to change the waveguide position  We simulated the waveguide with steps to check effects on the field distribution, it reduces the field strength  Using a waveguide without doorknob considerably eases the mounting and reduces the cost (as LHC)  Immediately after the coupler waveguide flange, there will be a flexible waveguide to reduce mechanical stresses  Nevertheless, a supporting tool will be necessary for the coupler waveguide, still to be studied 16/03/2010 16 Eric Montesinos / CERN-BE-RF-SR Doorknob / reduced height: ~ same field strength Two steps waveguide: slightly reduces the field strength LHC design with a possible conical coaxial extension to change the waveguide axis

17. Comparison 16/03/2010Eric Montesinos / CERN-BE-RF-SR 17 Item Coaxial water cooled Coaxial air cooled Cylindrical Air cooled A single window coupler Possible adjustable coupler Integration in the cryomodule Vertically above or below the cavity DC biasing Air cooled Matched window “Plug and play waveguide”

18. Coupling box  Will be used to:  Connect two couplers in the vertical position for conditioning  Storage and transport chamber with springs to damp shocks  Solid copper:  Low RF losses  Strong enough to sustain deformation due to strong pressure effects  Extra external mechanical adjustment for frequency tuning  Could be EB soldered or assembled from two parts:  Vacuum seal  Easy to clean, we want to re-use it for 250 couplers ! 16/03/2010 18 Eric Montesinos / CERN-BE-RF-SR Springs to avoid any shock while transporting

19. Construction process  We plan to follow an upgraded LHC coupler construction process:  Build all components: Metrologic controls Mechanical and thermal tests  In clean room (class 100): clean all parts in contact with beam vacuum with pure water or pure alcohol Particle counting to validate the cleaning  In clean room (class10): assemble a pair of couplers and mount them on a test cavity  Bake out  RF conditioning  In clean room (class 10): mounting of coupler with its double walled tube on SPL cavity Build all components In clean room: clean all parts in contact with beam vacuum In clean room: assemble a pair of couplers and mount them onto a coupling box Bake outRF conditioning Double walled tube and coupler mounted onto the cavity 16/03/2010 19 Eric Montesinos / CERN-BE-RF-SR Vacuum leak detections after each major operation

20. Construction process  To be carefully followed-up:  Assembly tooling  Handling with special gloves only, avoid contamination of surfaces by hydrocarbons, finger prints,…  Optimize the process to minimize the number of handlings  Avoid intermediate packing in polymeric sealed bags (contamination)  Specially designed transport containers  Visit tomorrow of the three facilities:  Building 252 class 100 clean room  Building 252 class 10 clean room  Building SM18 class 10 clean room  Would like advice on what we could improve for high gradient cavities 16/03/2010 20 Eric Montesinos / CERN-BE-RF-SR

21. Conditioning process  Install one cavity with its two power couplers and prepare for conditioning  List of interlocks and monitoring:  Vacuum gauges  Directional couplers  Light detector  Electron monitor  Thermal measurements  Gas analyzer  Air flow meter  Water flow meter (power load)  …  The tests will be done at CEA Saclay 16/03/2010 21 Eric Montesinos / CERN-BE-RF-SR TTF III power coupler test bench

22. Conditioning process 16/03/2010Eric Montesinos / CERN-BE-RF-SR 22  The conditioning loop will be the same as the one used since 1998 with the SPS and LHC couplers:  A first direct vacuum loop (red) ensures RF is never applied if pressure exceeds 5.0 x 10 -7 mbar  A second vacuum loop (blue), cpu controlled, executes the automated process  The interlock vacuum threshold of 5.0 x 10 -7 mbar will be chosen, guided by our experience, to protect the couplers, but also to have an as short as possible conditioning time  The settings are adjusted to have minimum attenuation under 1.0 x 10 -8 mbar and maximum attenuation over 2.5 x 10 -7 mbar (~40 dB dynamic range with the attenuator)

23. Conditioning process  The conditioning process will be similar to the LHC one:  The process always starts, under vacuum control, with very short pulses of 20 µs every 20 ms  Power level is increased using short pulses up to full power passing slowly through all power levels to avoid “de-conditioning”  Same procedure repeated for initially short then longer and longer pulses up to the maximum length  The conditioning process will be considered finished when the vacuum level decreases below a predefined level (1 x 10 -8 mbar for example), while ramping the maximum length pulse 16/03/2010 23 Eric Montesinos / CERN-BE-RF-SR

24. Double walled tube rough estimate: 15’000 CHF Coupling box rough estimate: 25’000 CHF 16/03/2010 24 Eric Montesinos / CERN-BE-RF-SR Part List coupling box RepNbDésignationMatière Prix matière (CHF) Prix MO (CHF) Prix global (CHF) 11COUVERCLE SUPERIEURCUIVRE OFE200016003600 21COUVERCLE INFERIEURCUIVRE OFE20008002800 31BRIDE ENTRÉEINOX 316 LN44412001644 41BRIDE SORTIEINOX 316 LN44412001644 51TUBE PIQUAGE VIDECUIVRE OFE15400415 61BRIDE VIDEINOX 316 LN164400564 Equipement de protection pour le transport 14500 Total5067560025167 Part List tube double SPL RepNbDésignationMatière Prix matière (CHF) Prix MO (CHF) Prix global (CHF) 11TUBE CONNECTION HELIUMINOX10400410 21FLASQUE VIDE D ISOLATIONINOX2000 4000 32CORPSINOX FORGE 3D150060007500 411/2 COQUILLESINOX5020002050 51TUBE CONNECTION HELIUMINOX10400410 Total35701080014370

25. SPL-CEA rough estimate: 53’000 CHF 16/03/2010 25 Eric Montesinos / CERN-BE-RF-SR Part List coupleur SPL type CEA RepNbDésignationMatière Prix matière (CHF) Prix MO (CHF) Prix global (CHF) 11BRIDE SUPERIEURE BODYCUIVRE10016001700 21ENTRETOISE SUPERIEUR BODYCUIVRE23016001830 31COUPELLE SUPERIEUR BODYCUIVRE18020002180 41RACCORD ANTENNECUIVRE80800880 51 BAGUE SUPERIEUR DE CENTRAGE ANTENNECUIVRE4010001040 61TUBE INTERIEUR CERAMIQUECUIVRE2510001025 71CERAMIQUEOXYDE D' ALUMINIUM30030003300 81ENTRETOISE CENTRALE INTERNE BODYCUIVRE1800801 91TUBE CONNECTION REFROIDISSEMENTINOX2400402 101PATTE CONNECTION REFROIDISSEMENTCUIVRE300400700 111CAPOT DE REFROIDISSEMENT BODYCUIVRE18020002180 121COUPELLE INFERIEURE BODYCUIVRE18020002180 131ENTRETOISE CENTRALE EXTERNE BODYCUIVRE18016001780 142TUBE DE BRIDE UHVCUIVRE5500505 151BRIDE UHVINOX10200210 161DETECTEUR 80025003300 171BRIDE INFERIEURE BODYINOX CUIVRE15014001550 181BRIDE UHV JAUGEINOX116400516 191JAUGE A VIDE PENNING IKR 070 900 201CONNECTION DOORKNOBSANTICORODAL20400420 211DOORKNOBSANTICORODAL15020002150 221BRIDE DOORKNOBSANTICORODAL7010001070 231GUIDE D' ONDEANTICORODAL30020002300 241ENTRETOISE GUIDE D' ONDEANTICORODAL10400410 251BRIDE GUIDE D' ONDEANTICORODAL20800820 261TUBE ALLEE REFROIDISSEMENTINOX2200202 271COUVERCLE ANTENNEINOX2200202 281JOINT TORIQUE Ø3EPDM2 2 291BRIDE COUVERCLE ANTENNECUIVRE6500506 301TUBE SORTIE REFROIDISSEMENTINOX2200202 311ANTENNE SUPERIEURECUIVRE FORGE150018003300 321VIS SPECIALE ACOUPLEMENT ANTENNESVIS INOX1400401 331CONNECTION ANTENNE SUPERIEURECUIVRE4500504 341JOINT TORIQUE Ø3EPDM2 2 351CANNE SUPERIEUREINOX10200210 361FIXATION CANNE INFERIEUREINOX5400405 371ACOUPLEMENT ANTENNECUIVRE FORGE80012002000 381ANTENNE INFERIEURECUIVRE FORGE17008002500 391BOUCHON ANTENNECUIVRE FORGE50200250 401CANNE INFERIEUREINOX20400420 411BOUCHON CANNEINOX5800805 421CANAL DE REFROIDISSEMENTINOX10200210 Total84703780046270

26. SPL-SPS rough estimate: 27’000 CHF 16/03/2010 26 Eric Montesinos / CERN-BE-RF-SR Part List coupleur SPL type SPS RepNbDésignationMatière Prix matière (CHF) Prix MO (CHF) Prix global (CHF) 11CAPOT DE PROTECTIONTOLE GRILLAGEE15400415 22BAGUE DE PROTECTION KAPTONPEEK NATUREL10004001400 31CONDENSATEUR EXTERNEANTICORODAL135800935 41KAPTON 10400410 51BAGUE DE SERRAGEANTICORODAL2200202 61CONDENSATEUR INTERNEANTICORODAL40800840 71CONTACT RFCUIVRE + DORAGE50200250 81SOCLE CONDENSATEURANTICORODAL35200235 91GUIDE D' ONDEANTICORODAL30020002300 101BONCHON GUIDE D' ONDEANTICORODAL35200235 111SOCLE BODYANTICORODAL35200235 121JOINT RFCUIVRE + DORAGE 0 131BODYANTICORODAL + CUIVRAGE8010001080 141CAPOT DE VENTILATIONINOX20500520 151JOINT PROFILE UEPDM21012 161JOINT TORIQUE Ø2.5EPDM151025 171BRIDE TITANETITANE40016416 181CERAMIQUE TITANISEEOXYDE D' ALUMINIUM30030003300 191EXTENTION JAUGE A VIDE (2 BRIDES + TUBE)INOX + CUIVRAGE15004001900 201JAUGE A VIDE PENNING IKR 070 900 211BRIDE JAUGE A VIDEINOX116400516 221BAGUE DE SERRAGE ANTENNEINOX210001002 231BAGUE FILETEEINOX516001605 241CANNEINOX20400420 251ANTENNE SUPERIEURECUIVRE170012002900 261INSERT TARAUDEINOX + ARGENTAGE10800810 271TUBE CERAMIQUE + INSERT INOXCUIVRE FORGE2008001000 281ANTENNE INFERIEURECUIVRE FORGE17008002500 291BOUCHON ANTENNECUIVRE FORGE50200250 Total86771793626613

27. SPL-LHC rough estimate: 30’000 CHF 16/03/2010 27 Eric Montesinos / CERN-BE-RF-SR Part List coupleur SPL type LHC RepNbDésignationMatière Prix matière (CHF) Prix MO (CHF) Prix global (CHF) 11CAPOT DE PROTECTIONTOLE GRILLAGEE15400415 22BAGUE DE PROTECTION KAPTONPEEK NATUREL10004001400 31CONDENSATEUR EXTERNEANTICORODAL135800935 41KAPTON 10400410 51CONDENSATEUR INTERNEANTICORODAL40800840 61CONTACT RFCUIVRE + DORAGE50200250 71SOCLE CONDENSATEURANTICORODAL35200235 81GUIDE D' ONDEANTICORODAL30020002300 91BONCHON GUIDE D' ONDEANTICORODAL35200235 101SOCLE BODYANTICORODAL35200235 111JOINT RFCUIVRE + DORAGE 0 121COLLET SUPERIEURCUIVRE FORGE80016002400 131CERAMIQUEOXYDE D'ALUMINE80020002800 141COLLET INFERIEURCUIVRE FORGE70016002300 151BODYCUIVRE180020003800 161BRIDE SUPERIEUR BODYINOX90400490 171BRIDE JAUGE A VIDEINOX116400516 181JAUGE A VIDE PENNING IKR 070 900 191BRIDE TOURNANTE BODYINOX500400900 201BRIDE UHV BODYINOX50016002100 211BAGUE DE SERRAGE ANTENNEINOX2400402 221CANNEINOX20200220 231BAGUE DE CENTRAGE ANTENNEINOX2400402 241ANTENNE SUPERIEURECUIVRE FORGE60012001800 251TUBE ANTENNECUIVRE FORGE200012003200 261BOUCHON ANTENNECUIVRE FORGE50200250 Total105351920029735

28. Mass production 16/03/2010Eric Montesinos / CERN-BE-RF-SR 28 Coaxial water cooled Coaxial air cooled Cylindrical Air cooled Unit prototype price: Coupler53 kCHF27 kCHF30 kCHF Eight bare couplers424 kCHF216 kCHF240 kCHF Unit price: Double walled tube15 kCHF Unit price: Coupling box25 kCHF Unit price: Miscellaneous (clean room, leak detections, bake out, transports, …) 15 kCHF Eight peripherals340 kCHF Eight couplers (+ 2 spare ceramics)775 kCHF550 kCHF600 kCHF Coupler unit price (no quantity reduction, including double walled tube 15kCHF, and Misc. 10kCHF) 78 kCHF52 kCHF55 kCHF 275 couplers (no test cavities, no conditioning process) 21’500 kCHF14’500 kCHF15’000 kCHF

29. New proposed schedule 16/03/2010 29 Eric Montesinos / CERN-BE-RF-SR Confirm the Saclay test stand availability in 2011: February and end of year?  Integrate advice and launch as soon as possible:  One pair of coaxial air cooled window  One pair of cylindrical air cooled window  Have 2 pairs ready for tests beginning 2011  Decide which ones to construct in March 2011 (still three possible choices)  Construct remaining couplers in 2011  Have 8 fully ready and conditioned couplers beginning 2012 Today: coupler review

30. Conclusion: still a lot to do…  Eight couplers could be ready within two years:  Necessarily based on existing designs and very well known processes  Coaxial air cooled and cylindrical air cooled versions to be tried:  Potentially inexpensive for mass production  Interesting for large machines  Keep the coaxial water cooled option open:  Study the modification of the cooling from water to air  Redesign the waveguide transition for: Less stress to the ceramic Easier DC biasing 16/03/2010 30 Eric Montesinos / CERN-BE-RF-SR

31. Many thanks for your patience 16/03/2010Eric Montesinos / CERN-BE-RF-SR