Multiple Beam Klystrons for Accelerators and Collider

Patrick Ferguson, Liqun Song, Lawrence Ives

Calabazas Creek Research, Inc.

20937 Comer Drive

Saratoga, CA 95070

(408) 741-8680

Patrick@CalCreek.com, RLIves@CalCreek.com

www.CalCreek.com

Calabazas Creek Research, Inc.

Leader in development of high power RF sources and components for fusion and high energy physics research. Products used in Europe, Asia, and the United States. Founded in 1994.

10 MW, W-Band Gyroklystron

Current Programs• 50 MW X-Band Multiple Beam

Klystron (MBK)• 201 MHZ, 5 MW MBK• 100 W, W-Band MEMS TWT• Improved cathodes for magnetron

injection guns• X-Band, 100 MW Sheet Beam Gun• Finite Element, Adaptive Mesh

Particle-In-Cell Code• Finite Element, Adaptive Mesh

Trajectory Code• High power windows and

waveguide components 500 kV Electron Gun for the University of Maryland

Additional information at www.CalCreek.com

Analytical Tools

• Gun and collector design – 3D Beam Optics Analysis, 3D OmniTrak, 2D Trak, 2D EGUN

• Magnetics – Maxwell 2D, Maxwell 3D

• Cavities – Superfish, HFSS, MAFIA

• Circuit – 21/2D KLSC, 3D MAGIC

• Thermal - ANYSYS

X-Band MBK Program

50 MW, 11.424 GHz MBK for accelerator research

Collector DesignCollector design requires 3D magnetics and

3D beam simulations.

5 MW, 201 MHz MBK for Tevatron

Number of Beams 8Frequency 201 MHzPower 5 MWEfficiency >55%Gain 46 dBMust operate linearly 15% below saturationMust fit in space available

Funded by U.S. Department of Energy Small BusinessInnovation Research Grants DE-FG03-004ER83916

Multiple Beam Fundamental Mode Cavity Configuration

Electron Gun Analysis

Circuit Analysis(1) Initial design of MBK circuit utilizes 2D MAGIC and KLSC. Consistency is required. Final design uses 3D MAGIC. All components cold tested before and after assembly.

Circuit Analysis(2)

3D MAGIC beam-RF Interaction

Induced RF voltage in the output

Window DesignWindow design performed with CCR’s scattering matrix code

CASCADE. Thermomechanical analysis uses ANSYS.

Anticipated Configuration

Magnet coils

Polepieces

Coaxial Output (2)

HV ceramic operates in air

10 MW, 201 MHz MBK for Tevatron

Number of Beams 8Frequency 201 MHzPower 10 MWEfficiency >55%Gain 46 dBMust operate linearly 15% below saturationMust fit in space available

Funded by U.S. Department of Energy Small BusinessInnovation Research Grants DE-FG03-004ER83916

Cost Trade-Offs

Klystron configuration based on total system cost, including power supply.

• Diversified Technologies Inc. provided cost comparison for solid state power supplies

• Number of beams based on power supply costs, cost of the electron gun, and cost of the klystron circuit

201 MHz MBK Status

• Phase I program successfully completed• Phase II proposal due April 13, 2005• Klystron and magnet would be built, tested,

and delivered in the Phase II program to Fermi National Accelerator Laboratory

DOE SBIR Solicitation

Grant applications are sought for new approaches for RF amplifiers for use in future Muon Collider. The RF amplifiers must have high peak power (>30 MW), 20 MHz (2 ms pulses) to 200 MHz (0.1 ms pulses). Higher power (>100 MW) at higher frequencies (from 30 microsec. At 400 MHz to 10 microsec. at 800 MHz) are also of interest. Pulse repetition rate compatibility = 15 Hz.

30 MW, 200 MHz MBK

Configuration assumes 12 beams.Beam Voltage 115 kVCurrent 468 AMicroperveance 12.0 (effective)Efficiency 55%Circuit Length 2.96 meters

100 MW, 800 MHz MBK

Configuration assumes 8 beamsBeam Voltage 250 kV (solid state supply)

Current 752 AMicroperveance 8.0 – effectiveEfficiency >55%Gain 50 dBOutput Power 119 MWCircuit Length 2.98 meters

Phase I SBIR proposal submitted to DOE in December 2004. Currently under review.

Summary• Multiple beam klystrons are currently being designed and built• X-Band MBK design is complete, gun was successfully tested, and klystron is being assembled• 201 MHz MBK initial design is complete. No significant problems are anticipated• Technology and experience available to successfully design and build MBK at other frequencies and higher power levels