X-Band RF Power Sources for Accelerator Applications

Mark Kirshner, Richard Kowalczyk, Craig Wilsen, Richard True, Ian Simpson and John Wray

L-3 Communications Electron Devices960 Industrial Road, San Carlos, CA 94070, USA

5th Collaboration Meeting on X-band Accelerator Structure Design and Test Program

May 17, 2011This presentation consists of information published and generally available to the public and does not contain controlled technical data as defined within the International Traffic in Arms

(ITAR) Part 120.10 or Export Administration Regulations (EAR) Part 734.7-11

2May 17, 2011Electron Devices Division

Accelerator System ArchitectureL-3 EDD Products

Accelerated e-beam collides with tungsten target to generateMeV-level x-rays

Electron gun injects kV-level e-beam

Linear accelerator

M-592e-gun

Klystron or magnetron provides MW-level RF power

to accelerate the e-beam

M-5051vacuum window

L-4040 thyratron for modulator

L-5822 S-band klystron

PM-2000XX-band

magnetronL-6145 X-bandklystron

M-5055X-band

RF driver

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X-Band Magnetron ProductsWater-Cooled, 9.3 GHz

PM-450X Series

PM-1100X Series

PM-2000X Series

400 kW peak 1.8 MW peak 2.2 MW peak

1200 W ave 1600 W ave 600 W ave

35 – 38 kV 36 – 38 kV 34 – 38 kV

34 A 88 A 110 A

8 s pulse length

4.5 s pulse length

2.5 s pulse length

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X-Band Coaxial MagnetronTypical Performance

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 20 40 60 80 100

Out

put P

ower

[MW

]

Peak Anode Current [A]

Peak Power

9.292

9.294

9.296

9.298

9.3

9.302

9.304

9.306

9.308

0 20 40 60 80 100

Freq

uenc

y [G

Hz]

Peak Anode Current [A]

Frequency Pushing

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0

100

200

300

400

500

600

700

800

0 5 10 15 20 25

Max

imum

Rep

etiti

on R

ate

(pps

)

Pulse Length (microseconds)

Stable operation

PM-450X MagnetronMaximum Operating Conditions

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L-6145 X-Band Klystron

• Robust X-band klystron capable of reliable high peak and average power operation

• 5 MW peak at 9.3 GHz• 20 kW average• 0.4 percent duty• 130 kV / 85 A (~1.8 P)• Solenoid focusing• Cathode-pulsed diode gun

• Operating parameters and physical configuration similar to EDD’s L-5822 S-band klystron to allow use of existing modulator

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3.0

3.5

4.0

4.5

5.0

5.5

9.28 9.29 9.30 9.31 9.32

Out

put P

ower

[MW

]

Frequency [GHz]

Bandwidth

X-Band KlystronL-6145 Test Data

Bandwidth at fixed drive

0

1

2

3

4

5

6

-10 10 30 50

Out

put P

ower

[MW

]

Input Power [W]

Peak Power

132 kV, 85 A

125 kV, 73 A

120 kV, 63 A

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Klystron Based RF Source

• The L6145 is now a production klystron • “Plug-and-play” with existing S-Band medical and industrial

linac modulators, available from multiple sources• Stangenes SI-21271 (275 Hz, 8 s)• Stangenes SSM 12-21 (200 Hz, 5.8 s)• ScandiNova K1

• The solenoid can be purchased fromStangenes Industries under part number SI-020348

• Klystron, solenoid, oil tank and modulator can be integrated in a compact package

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M-5051 RF Vacuum Window

• Water-cooled vacuum window• 5 MW peak, 20 kW average

• Multipactor suppressant coating is applied to both sides of the beryllia window ceramic

• Additional windows with dual vacuum flanges available for accelerator system

1

1.1

1.2

1.3

8.9 9.3 9.7

VS

WR

Frequency [GHz]

HFSSMeasurement

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M-5055 X-Band RF Driver

• Solid-state amplifier to drive the L-6145 X-band klystron• Center frequency 9.3 GHz• Available in 50 watt or 100 watt configuration

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Conclusion

• L-3 Communications Electron Devices Division (EDD) has developed an array of RF components operating at 9.3 GHz to address the growing market for X-band accelerators

• Coaxial magnetrons with 400 kW to 2.2 MW peak power and average power to 1600 watts

• Klystrons to 5 MW peak and 20 kW average power• X-band RF drivers to 100 watts• High power RF vacuum windows