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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) - PowerPoint PPT Presentation
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Linac4: Klystrons and Power Distribution
Nikolai Schwerg27/05/2010
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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 installation2
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Klystron-Gallery: LEP Klystrons
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RFQDTLCCDTLPIMS
LEP Klystron2.8-MW-Klystron 2.8 MW-Klystron LEP Klystron
Amplifier
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Klystron-Gallery: Final Version
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RFQDTLCCDTLPIMS
2.8 MW-Klystron
Amplifier
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Power Distribution Scheme – LEP Klystrons
5[Courtesy of J-P. Corso]
LEP Klystrons LEP Circulators Ferrite Loads Cavities
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Power Distribution Scheme – 2.8 MW Klystron
[Courtesy of J-P. Corso]0°
0°
180°0°
Δ Σ
2.8 MW Klystron
Folded Magic-Tee
LEP Circulators
Ferrite Loads Cavities
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Power Distribution Scheme – Alternative Waveguide Routing
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[Courtesy of J-P. Corso]
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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
8
0°
0°
18
0°
0°
ΔΣ
2.8 MW Klystron
Magic-Tee
2.8 MW Circulator
Ferrite Load
Cavities
Ferrite Load
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Amplitude Phase
Power Splitter
Magic-Tee
Quantitative Approach
9
• 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!)
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Test-Stand in Bat. 112
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CCDTL/PIMS/DTL
Klystron Preparation
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
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Waveguide Connections
11[Courtesy of J-P. Corso]
• Determine: Waveguide length to Cavities Number and Type of Bends
• Derive Phase Difference
• 3-Post Phase Shifter Being built
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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
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Picture by MEGAindustries: Folded Magic-tee in WR650
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Thank you for your Attention
-- Discussion --
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Klystron Replacement
14As presented by Olivier Brunner
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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
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Picture by MEGAindustries: Folded Magic-tee in WR650
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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)
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Powering Schemes
17
160 MeV100 MeV50 MeV3 MeV
6 m 19 m 25 m 22 m3.7 m
RFQ DTL CCDTL PIMS
LEP Klystron 2.8-MW-Klystron2.8 MW-KlystronLEP Klystron
Amplifier
RFQ DTL CCDTL PIMS
2.8 MW-Klystron
Amplifier
Ph
ase
IP
ha
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I