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

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Presentation on theme: "Possible proposed designs Part II : designs comparison SPL power coupler 16/03/2010Eric Montesinos / CERN-BE-RF-SR."— Presentation transcript:

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/ 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/ 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/ 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/ 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/ 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/ 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/ 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/ 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/ 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/ 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] CEA LHC SPS /03/ Eric Montesinos / CERN-BE-RF-SR SPL-CEA SPL-SPS SPL-LHC

15 Comparison: Field Strength 16/03/ 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), MV/m Riley, Lewis A. Dielectrics 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/ 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/ 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/ 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/ 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/ 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 mbar  A second vacuum loop (blue), cpu controlled, executes the automated process  The interlock vacuum threshold of 5.0 x 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 mbar and maximum attenuation over 2.5 x 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 mbar for example), while ramping the maximum length pulse 16/03/ Eric Montesinos / CERN-BE-RF-SR

24 Double walled tube rough estimate: 15’000 CHF Coupling box rough estimate: 25’000 CHF 16/03/ Eric Montesinos / CERN-BE-RF-SR Part List coupling box RepNbDésignationMatière Prix matière (CHF) Prix MO (CHF) Prix global (CHF) 11COUVERCLE SUPERIEURCUIVRE OFE COUVERCLE INFERIEURCUIVRE OFE BRIDE ENTRÉEINOX 316 LN BRIDE SORTIEINOX 316 LN TUBE PIQUAGE VIDECUIVRE OFE BRIDE VIDEINOX 316 LN Equipement de protection pour le transport Total Part List tube double SPL RepNbDésignationMatière Prix matière (CHF) Prix MO (CHF) Prix global (CHF) 11TUBE CONNECTION HELIUMINOX FLASQUE VIDE D ISOLATIONINOX CORPSINOX FORGE 3D /2 COQUILLESINOX TUBE CONNECTION HELIUMINOX Total

25 SPL-CEA rough estimate: 53’000 CHF 16/03/ Eric Montesinos / CERN-BE-RF-SR Part List coupleur SPL type CEA RepNbDésignationMatière Prix matière (CHF) Prix MO (CHF) Prix global (CHF) 11BRIDE SUPERIEURE BODYCUIVRE ENTRETOISE SUPERIEUR BODYCUIVRE COUPELLE SUPERIEUR BODYCUIVRE RACCORD ANTENNECUIVRE BAGUE SUPERIEUR DE CENTRAGE ANTENNECUIVRE TUBE INTERIEUR CERAMIQUECUIVRE CERAMIQUEOXYDE D' ALUMINIUM ENTRETOISE CENTRALE INTERNE BODYCUIVRE TUBE CONNECTION REFROIDISSEMENTINOX PATTE CONNECTION REFROIDISSEMENTCUIVRE CAPOT DE REFROIDISSEMENT BODYCUIVRE COUPELLE INFERIEURE BODYCUIVRE ENTRETOISE CENTRALE EXTERNE BODYCUIVRE TUBE DE BRIDE UHVCUIVRE BRIDE UHVINOX DETECTEUR BRIDE INFERIEURE BODYINOX CUIVRE BRIDE UHV JAUGEINOX JAUGE A VIDE PENNING IKR CONNECTION DOORKNOBSANTICORODAL DOORKNOBSANTICORODAL BRIDE DOORKNOBSANTICORODAL GUIDE D' ONDEANTICORODAL ENTRETOISE GUIDE D' ONDEANTICORODAL BRIDE GUIDE D' ONDEANTICORODAL TUBE ALLEE REFROIDISSEMENTINOX COUVERCLE ANTENNEINOX JOINT TORIQUE Ø3EPDM BRIDE COUVERCLE ANTENNECUIVRE TUBE SORTIE REFROIDISSEMENTINOX ANTENNE SUPERIEURECUIVRE FORGE VIS SPECIALE ACOUPLEMENT ANTENNESVIS INOX CONNECTION ANTENNE SUPERIEURECUIVRE JOINT TORIQUE Ø3EPDM CANNE SUPERIEUREINOX FIXATION CANNE INFERIEUREINOX ACOUPLEMENT ANTENNECUIVRE FORGE ANTENNE INFERIEURECUIVRE FORGE BOUCHON ANTENNECUIVRE FORGE CANNE INFERIEUREINOX BOUCHON CANNEINOX CANAL DE REFROIDISSEMENTINOX Total

26 SPL-SPS rough estimate: 27’000 CHF 16/03/ 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 GRILLAGEE BAGUE DE PROTECTION KAPTONPEEK NATUREL CONDENSATEUR EXTERNEANTICORODAL KAPTON BAGUE DE SERRAGEANTICORODAL CONDENSATEUR INTERNEANTICORODAL CONTACT RFCUIVRE + DORAGE SOCLE CONDENSATEURANTICORODAL GUIDE D' ONDEANTICORODAL BONCHON GUIDE D' ONDEANTICORODAL SOCLE BODYANTICORODAL JOINT RFCUIVRE + DORAGE 0 131BODYANTICORODAL + CUIVRAGE CAPOT DE VENTILATIONINOX JOINT PROFILE UEPDM JOINT TORIQUE Ø2.5EPDM BRIDE TITANETITANE CERAMIQUE TITANISEEOXYDE D' ALUMINIUM EXTENTION JAUGE A VIDE (2 BRIDES + TUBE)INOX + CUIVRAGE JAUGE A VIDE PENNING IKR BRIDE JAUGE A VIDEINOX BAGUE DE SERRAGE ANTENNEINOX BAGUE FILETEEINOX CANNEINOX ANTENNE SUPERIEURECUIVRE INSERT TARAUDEINOX + ARGENTAGE TUBE CERAMIQUE + INSERT INOXCUIVRE FORGE ANTENNE INFERIEURECUIVRE FORGE BOUCHON ANTENNECUIVRE FORGE Total

27 SPL-LHC rough estimate: 30’000 CHF 16/03/ 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 GRILLAGEE BAGUE DE PROTECTION KAPTONPEEK NATUREL CONDENSATEUR EXTERNEANTICORODAL KAPTON CONDENSATEUR INTERNEANTICORODAL CONTACT RFCUIVRE + DORAGE SOCLE CONDENSATEURANTICORODAL GUIDE D' ONDEANTICORODAL BONCHON GUIDE D' ONDEANTICORODAL SOCLE BODYANTICORODAL JOINT RFCUIVRE + DORAGE 0 121COLLET SUPERIEURCUIVRE FORGE CERAMIQUEOXYDE D'ALUMINE COLLET INFERIEURCUIVRE FORGE BODYCUIVRE BRIDE SUPERIEUR BODYINOX BRIDE JAUGE A VIDEINOX JAUGE A VIDE PENNING IKR BRIDE TOURNANTE BODYINOX BRIDE UHV BODYINOX BAGUE DE SERRAGE ANTENNEINOX CANNEINOX BAGUE DE CENTRAGE ANTENNEINOX ANTENNE SUPERIEURECUIVRE FORGE TUBE ANTENNECUIVRE FORGE BOUCHON ANTENNECUIVRE FORGE Total

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/ 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/ Eric Montesinos / CERN-BE-RF-SR

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


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