1. X Band Vacuum Devices Presented by: Tony Johns,
CPI Europe, Surrey, England
Tel: +44 (1932) Fax: +44 (1932)
Mobile: +44 (7880)
With material from: Adam Balkcum, Steve Lenci, Mike Cusick, Peter Kolda
CPI, Palo Alto, California, USA
Introduction
Tony’s experience and history with company
Acknowledge contributors to presentation

2. Historical Timeline
1990: Eimac awarded an Emmy for technological achievement Klystrode IOT
1965: Eitel-McCullough merges with Varian Associates to form Eimac Division
2001: Current management team takes leadership
2007: CPI acquires Malibu Research Associates
1935: Eimac Division founded as Eitel McCullough, Inc.
1954: CMP Division is established in Canada
1930
1940
1950
1960
1970
1980
1990
2001
2004
2006
2007
1948: CPI is originated as founding technology group of Varian Associates
1959: Varian Associates acquires Bomac Labs in Beverly, MA.
1971: Varian integrates SFD Labs of Union, NJ with Beverly MA, division renamed BMD
1995: Leonard Green & Partners, L.P. purchases entire Electron Devices Business from Varian and forms CPI
2004: Cypress Group Acquires CPI
CPI Acquires Econco Broadcast Service
2006: CPI stock publicly trades -NASDAQ: “CPII"
MPP & Eimac divisions consolidate
It’s all on the slide

3. Communications & Power Industries Inc.
Publicly held
NASDAQ: “CPII"
Established in August 1995
Worldwide Sales and Service Organization
1,700 Employees Worldwide
Six autonomous business units:
BMD Beverly, MA, U.S.A.
CMP Georgetown, ONT, Canada
Econco Woodland, CA, U.S.A.
MPP Palo Alto, CA, U.S.A
Satcom Georgetown, ONT, Canada (Manufacturing)
Palo Alto, CA, U.S.A (R&D, Marketing, Service)
Malibu Research Associates, Camarillo, CA, U.S.A.
Again, all on the slide

4. Manufacturing/R&D Locations2
Manufacturing/R&D Locations
Georgetown, Ontario, Canada
Communications & Medical Products Division
—Manufacturing Operation
Woodland, California
Quick trip to US and Canada
Palo Alto, California
—R&D, Marketing, Service
Beverly, MA Beverly Microwave Products Division
Camarillo, CA
Malibu Research Associates

5. Broad Product Offering Consultative Engineering Services
CPI Specialities
High Power
High Efficiency
Broad Product Offering
Consultative Engineering Services
A little motherhood and apple pie as we Yanks say.

6. Inductive Output Tubes Magnetrons Cross-Field Amplifiers
Products Supplied
Klystrons
Gyrotrons
Helix TWTs
Coupled Cavity TWTs
Ring Bar TWTs
Power Grid Tubes
Inductive Output Tubes
Magnetrons
Cross-Field Amplifiers
X-Ray Generators
Satellite Communications amplifiers
Antennas
CPI provides a broad range of microwave power sources.
The predominant products for accelerator application are klystrons, Inductive Output Tubes (IOT’s), and magnetrons
IOTs are suited to low frequency (200 MHz – 1.5 GHz) and are important in the accelerator market
Gyrotrons are high frequency devices (28 GHz to 140 GHz) and are primarily used in fusion energy experiments
CPI BMD operation has built a number of window-couplers for scientific use

7. VTX6389G5 Helix X Band Products Typical Operating Parameters
Frequency GHz
Power Output CW 2.5 kW
Efficiency 59 %
Beam Voltage 15 kV
Beam Current 1 A
The VTX6389G5 X band TWT, shown in the upper left, is one of the products in a broad array of helix devices offered by CPI. The 6389G5 is a 2.5 kW CW device and it operates with a prime power of 7.4 kilowatts. It has small signal gain (before gain compression) of 62 dB. Key features of helix devices are their broad band frequency performance with extremely linear power over that band. The gain variation typical of this particular device is 1.2 dB. This device is important in communications systems where multiple signals are amplified simultaneously. This device is typical of the state of the art in helix traveling wave tube technology.

8. VKL-8301 Multiple Beam Klystron
Typical Operating Parameters
Frequency GHz
Peak Power Output 10 MW
Ave. Power Output 150 kW
Power Asymmetry 0.7 %
Efficiency 59 %
Beam Voltage 120 kV
Beam Current 141 A
Microperveance 3.4
RF Pulse Length 1.5 ms
Saturated Gain 49 dB
Cathode loading 2.2 A/cm2
The prototype MBK is at DESY Hamburg
Presently building a 2nd generation MBK that is designed to operate horizontally. It was just loaded in the test stand and results are expected in January
The VKL-8301 is a recent high power klystron that was developed for the superconducting accelerator of the European X-ray Free Electron Laser. Although this particular klystron operates in L-band, it is an example of the new types of devices that CPI is currently investigating. This klystron is a higher-order mode multiple beam klystron. It has six cathodes set on a large bolt circle that drive TM02 (or higher-order mode) cavities. The advantage of multiple beams is that more of the beam power is carried in the beam current so that for a given rf output power, the operating voltage can be greatly lowered. Further, because the individual electron guns have a low microperveance, high efficiency can be maintained (as efficiency increases with lower microperveance): a distinct advantage for a large-scale accelerator. This klystron produced 10 MW peak, 150 kW average rf output power with an efficiency of 59% at a beam voltage of only 120 kV. By comparison, a standard single beam klystron with comparable efficiency would have operated at approximately 240 kV. Another advantage of this device is the use of large cavities which allows the cathodes to be placed on a large bolt circle. This allows the cathodes themselves to be large which lowers the cathode current density loading. As shown in the table, the loading is about 2 amps per square centimeter which equates to over 100,000 hours of expected cathode life. CPI is currently working on a new version of this klystron for the same application. It will be smaller in size for reduced cost but will still have low cathode current density loadings and a long life. The device is currently in test and the preliminary results are very encouraging.
Used in European X-Ray FEL at DESY. Potential use in ILC. Horizontal version in progress with integrated X-ray shielding and cart currently in test.

9. Typical Operating Parameters
VKL-9130 IOT
Typical Operating Parameters
Frequency GHz
Peak Power 90 kW
Beam Voltage 42 kV
Beam Current 3.4 A
Bandwidth (-1 dB) 2 MHz
Gain 20 dB
Efficiency 60 %
IOT’s are “low” frequency devices (up to 1.5 GHz)
One application of this integral cavity version is operated in pulsed mode up 90 kW peak with 1.5 msec pulse lengths at 10 Hz.
The tube can also be operated at 30 kW CW
Currently developing a higher power version at 120 kW CW
Recent testing successful at FZD
Currently developing 120 kW CW device

10. Typical Operating Parameters
VKX-7864B Klystron
250 kW CW in X-Band
Typical Operating Parameters
Power Output kW
Beam Voltage 51 kV
Beam Current A
Supply Power kW
Efficiency 44 %
Frequency GHz
1dB Bandwidth 60 MHz
Saturated Gain 45 dB
Cavities 6
Cooling Method liquid
The VKX-7864B is a high power CW X-band klystron. It is used by NASA’s Jet Propulsion Laboratory in their Deep Space Radar Transmitter. The klystron itself is mounted directly into the base of the antenna. The tube produces 250 kW CW at 8.56 GHz with 44% efficiency and 45 dB of gain to create a combined power of 500 kW CW. As can be seen, the collector accounts for most of the size and weight of the klystron. That is because it must be capable of dissipating the full beam power (more than 550 kW CW).

11. VTX-5681 Coupled Cavity TWT
100 kW Pulsed in X-band
Typical Operating Parameters
Frequency GHz
Peak Power Output 100 kW
Duty 35 %
Saturated Gain 49 dB
Bandwidth (-1 dB ) 1 GHz
Beam Voltage 45 kV
Beam Current 11 A
Liquid cooled
Solenoid focused
Modulating anode controlled beam (50KV swing)
Device used in high power radar
Units may be combined for added power
Phase matching possible over the desired bandwidth
State of the art in high power coupled cavity traveling wave tube technology

12. VKX-7841 Klystron
Used in experimental accelerator research circa 1980, 5 were made. Very compact.
Typical Operating Parameters
Frequency GHz
Peak Power Output kW
Ave. Power Output 0.2 kW
Saturated Gain 71 dB
Bandwidth (-1 dB ) 45 MHz
Efficiency 28 %
Beam Voltage 8 kV
Beam Current 30 A
The VKX-7841 was an experimental tube developed in the late ‘70s for a small experimental accelerator. It had a fairly high peak power of 600 kW at 9.5 GHz with a modest average power of only 200 W required for the application. It used periodic permanent magnet focusing and was cooled by a water cooled baseplate which made for a very compact device. The high voltage hook-up to the electron gun was also unusual and compact. It consisted of a plug into a ceramic socket directly on the gun which eliminated the need for any oil even though it was operating at 78 kV. Five of these devices were made.

13. Market drivers CPI Response Requirements for higher efficiency
Recent Advancements
Market drivers
Requirements for higher efficiency
Desire for lower beam voltages
Need for smaller size
CPI Response
Sheet Beam Klystron
PPM Focused Klystron

14. Typical Operating Parameters
VKX-7993 Klystron
2.7 MW Pulsed
Typical Operating Parameters
Frequency GHz
Peak Power 2.7 MW
Peak Power (goal) 5.5 kW
Saturated Gain 52 dB
Bandwidth (-1 dB ) 65 MHz
Efficiency 43 %
Beam Voltage 120 kV
Beam Current 52 A
The VKX-7993 is a modern, high power and compact X-band amplifier. It nominally produces 2.7 MW peak and 5.5 kW of average power at 9.3 GHz but has been operated as high as 3.3 MW. The amplifier has a fairly high gain of 52 dB with a reasonably good efficiency of 43%. Periodic permanent magnetic focusing was used to reduce its size and weight. The complete klystron with integrated X-ray shielding weighs only 60 pounds and is 24 inches long.
Compact device, recently in production

15. VKX-8293A Sheet Beam Klystron
Sheet Beam Technology
Typical Operating Parameters
Frequency GHz
Peak Power Output 2.7 MW
Ave. Power Output 0.3 kW
Saturated Gain 42 dB
Efficiency 25 %
Beam Voltage 76 kV
Beam Current 144 A
First of a kind device!
Goal is 5 MW peak and XX% efficiency.
CPI and our customer were very pleased in achieving 2.7 MW on the prototype. Presently being rebuilt with minor corrections to the beam optics. Expect test results in January.
Note the target operating voltage of 76 kV. Typical single beam klystron would require operation at 130 kV for 5 MW of output power.
Device is PPM focused.

16. Sheet Beam Klystron The device advances the state of the art.
Accelerating cavity fields are uniform across the web of the beam (X-dimension) by operating individual cavities at their cutoff frequency.
SBKs cavities are overmoded transversely to the beam and usually require multiple gaps in the direction of the beam (Z-dimension) in order to improve their coupling to the beam. A “mode forest” results, but it always possible to move the various modes and avoid interference with the operating frequency.
The SBK is a single-frequency amplifier, but, pound-for-pound the most powerful among linear beam tubes.

17. Sheet Beam Formation Drift Tunnel Cathode Focus Electrode Anode
Beam Direction
Electron gun of a sheet beam device.
NOTE – the light blue represents the region between the Cathode/Focus Electrode and the anode, as well as the beam tunnel

18. VKX-8293A Sheet Beam Klystron
Beam transmission was 63% for above parameters.
Best transmission was 94% at a much lower operating voltage.
Cathode position will be adjusted to improve transmission.

19. X band frequency range fertile
Conclusions
X band frequency range fertile
Efficiency continues to improve, over 60%
Size of products shrinking
Modern design codes allow complex analysis of beam dynamics
New RF structures possible
Power outputs from hundreds of watts to tens of megawatts
Attracting new engineers into vacuum device field