Preparation of RF Power Couplers For the Tesla Test Facility

Transcription

1 Preparation of RF Power Couplers For the Tesla Test Facility Axel Matheisen 1 **Feng Zhu 2 *** for the TESLA collaboration* 1 ) Deutsches Elektronen-Synchrotron DESY Notkestraße 85, D Hamburg, Germany 2) Ph.D. student from Institute of Heavy Ion Physics, Peking University Beijing ,China *TESLA Collaboration: Armenia: Ervin Physics Institute, P.R. China: IHEP Beijing, Tsinghua Univ., Finland: Inst. Of Physics Helsinki, France: DSM/DAPHNIA Saclay, IN2P3/IPN Orsay, IN3P3/LAL Orsay Germany: RWTH Aachen, BESSY Berlin, HMI Berlin, MBI Berlin, TU Berlin, TU Darmstadt, TU Dresden, Univ. Frankfurt, GKSS Geesthacht, DESY Hamburg& Zeuthen, Univ. Hamburg, FZK Karlsruhe, Univ. Rostock, Univ. Wuppertal, Italy: INFN Frascati, INFN Legnaro, INFN Milano, INFN Roma 2, Japan: KEK, Poland: Inst. Of Nuclear Physic Cracow, Univ. Univ. of Mining&Metallurgy Cracow, Soltan Inst. Of Nuclear Studies Otwock-Swierk, Polish Acad. Of Science Warsaw, Polish Atomic Energy Academy Warsaw, Univ. Warsaw, Switzerland; CERN, Russia: JINR Dubna, MEPhI Moscow, INP Novosibirsk, BINP Protvino, IHEP Protvino, INR Troitsk, USA: Argonne National Lab., Cornell Univ., FNAL Batavia, Fermilab, Thomas Jefferson National Accelerator Facilities Newport News, UCLA Los Angeles. ** axel.matheisen@desy.de ***zhu@herant.desy.de

2 Overview on talk Introduction design of Couplers for TTF Preparation Process (standardized for measurements) Measurement on particle contamination Conclusion

3 DESY 9 cell structure: Frequency : 1.3 Ghz No of cells: 9 RF equipment of TTF Cavity: 1 Power coupler 2 HOM couplers 1 RF Pick up probe.

4 TTF / TESLA Cryogenic modules DESY Cryogenic modules: 8 cavities; 1 BPM Cryogenic modules: assembled until : 5 Modules test s with electron beam until end of : 4+1 (1;2;3;1*;superstructure ) Cavity string in cleanroom Module assembly in TTF tunnel

5 General design criteria of TTF / TESLA couplers 2 independent parts and vacuum systems (cold and warm part) 2 RF ceramic windows.

6 Cold Ceramic window cold part: temperature level 2 to 70 K directly connected to the Cavity vacuum!. warm Ceramic window warm part: temperature level of 70 K to 300 K separate vacuum system of insulation vacuum quality.

7 Power coupler designs for TTF cold part Coupler type FNAL (F) DESY (TTF3) FRZ ( R ) DESY (D1) Coupling adjustable adjustable fixed adjustable Operation pulsed pulsed continuous pulsed Ceramic window design conical cylindrical conical cylindrical Inner conductor Hollow double tube tube tube tube bellow Outer conductor bellow bellow tube tube

8 Cleaning procedure of power couplers standard cleaning (StC) for test of cold parts in respect of particle contamination Ultrasonic cleaning (US st ) Clean water rinse (CWR st) Time: Us power: Temperature: Detergent: Concentration: Process: Filtration: Exchanges: Frequency: 20 Minutes 10 W /liter 50 C Ticopure 33 3% circulation of water; inline particle filter 2 µm ; manual movement of parts every 1-3 min Rinsing water: Filtration: Temperature: rinsing: spraying: spraying steps: Process end: Drying: ultra pure water 18Mohm cm 0,04 µm point of use filter 20 C continuous water jet 4 bar (manually) 5 Times water resistivity >=14 Mohm cm class 10 laminar flow for 12 h

9 Cleaning process sequences for cold power coupler s Outside: US st CWR st Dry in class 10 Inside Exception: After machining of couplers US st added to inside Inside CWRst Dry in class 10 Coupler processing Outside: US st CWR st Dry in class 10 Inside Blow with Ultra pure ionized gas only Assembly to cavity

10 Quality control of Particle contamination Probe Position 2 Ionized N2 gas jet ultra clean gas particle filter size <=0,04µm Probe Position 1

11 Results of particle measurements short side of coupler ( coaxial line to warm window ) TTF 3 Coupler D1 coupler F coupler typical particle decay on coupler short side total counts µm time (Min) R coupler short side

12 Results of particle measurements after first and 2 nd StC for F and TTF Type coupler long side of coupler ( cold window to cavity ) (Cumulative numbers shown) counts µm time (Min) Similar results found on TTF 1-2 coupler D1 long first a D1 long 2nd 25 F long 1st F long 2nd

13 Results of particle measurements after first StC for R and TTF 3 Type coupler (Cumulative numbers shown) counts 0,3-10 µm time (Min) R long D3-22 long D3-21 long

14 10000 total counts 0,3-10 µm D1 long first a D1 long 2nd F long 1st time ( Minutes) F long 2nd counts 0,3-10 µm R long TTF3-22 long time (Min) TTF3-21 long typical particle decay on coupler short side total counts µm Where is the difference? time (Min) R coupler short side

15 Power coupler designs for TTF cold parts Coupler type FNAL (F) TTF3 (T3) FRZ ( R ) DESY (D1) Coupling Adjustable adjustable fixed adjustable Operation pulsed pulsed continuous pulsed Ceramic window design conical cylindrical conical cylindrical Inner conductor Hollow double tube tube tube bellow tube Outer conductor bellow bellow tube tube Fabrication Fabrication with normal industry facilities and processes StC steps introduced in fabrication / transport boxes and clean areas Fabrication with normal industry facilities and processes Fabrication with normal industry facilities and processes

16 Conclusion No significant influence on ceramic window design (cylindrical / conical) versions observed Conical window F coupler needed special treatment and tooling Conical window R coupler good results after first standard cleaning No significant influence of Bellows in coaxial line observed D1 coupler (bellow outside) additional cleaning procedures and tools F / TTF 1+2 coupler (below in coax line) adopted cleaning procedures/ tools TTF 3 couples (bellow in coax line) good results after 1 st StC

17 Significant influence on Accessibility of ceramic observed All short sides easy to clean R design relative short tube on cavity side showed lower particle contamination short and wide line have better access (others than 50 ohm lines for coupler design possible? ) Significant influence on fabrication observed TT3 design showed lower particle contamination even if the design was not changed!

18 But for successful operation on s.c. cavities not only the design, fabrication and preparation are necessary for a successful application on s.c cavities Installation to the cavities

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