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Linac4: Klystrons and Power Distribution Nikolai Schwerg 27/05/2010. Starting Point: Re-use LEP RF equipment. Klystrons 20 LEP Klystrons (3 Manufacturers) together 50 years of operation left Re-tuning necessary Maximum power ? Circulators 29 AFT-Circulators (different specifications)
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Linac4: Klystrons and Power DistributionNikolai Schwerg27/05/2010
Starting Point: Re-use LEP RF equipment • Klystrons • 20 LEP Klystrons (3 Manufacturers) • together 50 years of operation left • Re-tuning necessary • Maximum power ? • Circulators • 29 AFT-Circulators (different specifications) • Reflected Power only 300 kW (for most circulators) • Constrains • Phase and Amplitude for DTLs • Space for PIMSs • Similar design for all whole installation
Klystron-Gallery: LEP Klystrons RFQ DTL CCDTL PIMS Amplifier LEP Klystron 2.8 MW-Klystron LEP Klystron 2.8-MW-Klystron
Klystron-Gallery: Final Version RFQ DTL CCDTL PIMS Amplifier 2.8 MW-Klystron
Power Distribution Scheme – LEP Klystrons Ferrite Loads LEP Klystrons LEP Circulators Cavities [Courtesy of J-P. Corso]
Power Distribution Scheme – 2.8 MW Klystron Folded Magic-Tee 2.8 MW Klystron Ferrite Loads Cavities Σ LEP Circulators 0° 0° 180° 0° Δ [Courtesy of J-P. Corso]
Power Distribution Scheme – Alternative Waveguide Routing [Courtesy of J-P. Corso]
Power Distribution Scheme – Alternative 2.8 MW Circulator • AFT claims to be able to built a 2.8 MW circulator without SF6 • Required: • Offer – Price? • Prototype for Testing Magic-Tee 2.8 MW Klystron 2.8 MW Circulator Cavities Ferrite Load Ferrite Load Σ 0° 0° 180° 0° Δ
Quantitative Approach • Use S-Parameters: • Ideal, e.g. Magic-Tee, Cavity, … • Measured, e.g. LHC Circulator as function of T and I • Solve for: • Cavity input signal • Reflection to Klystron • Compare for all Working Points (thousands!)
Test-Stand in Bat. 112 • Klystrons • Tuning of LEP Klystron • Montage and Testing of HV-Box • High Power Test • Circulators • High Power Test • Cavities RP? • Commissioning • Test of Full Installation • Folded Magic-Tee • Coupling between Circulators • Higher Order Modes • Running by end of 2010 CCDTL/PIMS/DTL Klystron Preparation
Waveguide Connections • Determine: • Waveguide length to Cavities • Number and Type of Bends • Derive Phase Difference • 3-Post Phase Shifter • Being built [Courtesy of J-P. Corso]
Ongoing Activities and Open Questions • Components: • Performance of the Folded Magic-Tee • Properties of 2.8 MW Circulator • RF Power Distribution Layout: • Waveguide Length • Phase Shifter • Coupling of Circulators • Cost and Risk Comparison • Testing: • Building Test-Stand in Bat. 112 • Schedule for Cavity • Components and Full Layout Picture by MEGAindustries: Folded Magic-tee in WR650
Thank you for your Attention -- Discussion --
Klystron Replacement As presented by Olivier Brunner
Folded Magic-Tee • Specifications: • Frequency: 352 MHz • Insertion loss: < 0.1 dB • Isolation between ports 1 and 2: > 37 dB • Balance between ports 2 and 4: < 0.2 dB • VSWR: 1.10:1 MAX (-26 dB) • Power: Peak 2.8 MW Average 10 kW or 150 kW • These values are identical to the values of a standard magic-tee of the same supplier Picture by MEGAindustries: Folded Magic-tee in WR650
Design Constrains / Guidelines • Mechanical: • Limited space in Klystron Hall (approx 3.50 m width) • RF: • Minimum Reflection to Klystron • Higher Order Mode Compensation • Phase and Amplitude balance between both Cavities • Prevention of Arcing • Installation: • Using an identical Design for all Klystrons • Considering two Variants: LEP Klystrons and new Klystrons • Operation: • (Tuneablity) • Accessibility of Loads and Circulators (Ferrite Breaking)
Powering Schemes RFQ DTL CCDTL PIMS Phase I Amplifier LEP Klystron 2.8 MW-Klystron LEP Klystron 2.8-MW-Klystron 6 m 3.7 m 19 m 25 m 22 m Phase II RFQ DTL CCDTL PIMS 50 MeV 100 MeV 160 MeV 3 MeV Amplifier 2.8 MW-Klystron 17