60 GHz gyrotron development program. Final report, April 1979-June 1984

Technical Report · Wed Jan 01 00:00:00 EST 1986

DOI:https://doi.org/10.2172/5626572· OSTI ID:5626572

Shively, J. F.; Bier, R. E.; Caplan, M.; Cheng, M. K.; Choi, E.; Conner, C. C.; Craig, L. J.; Evans, S. J.; Evers, S. J.; Felch, K. L.

The original objective of this program was to develop a microwave amplifier or oscillator capable of producing 200 kW CW power output at 110 GHz. The use of cyclotron resonance interaction was pursued, and the design phases of this effort are discussed. Later, however, the program's objective was changed to develop a family of oscillators capable of producing 200 kw of peak output power at 60 GHz. Gyrotron behavior studies were performed at 28 GHz to obtain generic design information as quickly as possible. The first experimental device at 60 GHz produced over 200 kw of peak power at a pulse duration of 20 ..mu..s. Heating problems and mode interference were encountered. The second experimental tube incorporated an optimized gun location but also suffered from mode interference. The third experimental tube included modifications that reduced mode interference. It demonstrated 200 kw of peak output at 100 ms pulse duration. The fourth experimental tube, which used an older rf circuit design but in a CW configuration, produced 71.5 kW CW. The fifth experimental tube incorporated a thinner double-disc output window which improved window bandwidth and reduced window loss. This tube also incorporated modifications to the drift tunnel and cavity coupling, which had proven successful in the third experimental pulse tube tests. It produced 123 kW of CW output power at 60 GHz rf load coolant boiling and tube window failure terminated the tests. A new waterload was designed and constructed, and alternative window designs were explored. A secondary task of developing a 56 GHz CW tube produced in excess of 100 kW CW at this alternate frequency. Testing of the sixth experimental tube resulted in operation at CW output power in the range of 200 to 206 kW for an hour. Output mode purity of the seventh experimental tube was measured at 95% TE/sub 02/. The tube was operated for about forty-five minutes with CW power output over 200 kW.

• Research Organization: Varian Associates, Inc., Palo Alto, CA (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5626572
• Report Number(s): ORNL/Sub-79-21453/21; ON: DE86012488
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

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42 ENGINEERING
43 PARTICLE ACCELERATORS
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RESEARCH PROGRAMS
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GHZ RANGE 01-100
GHZ RANGE 100-1000
INTERFERENCE
POWER RANGE 10-100 KW
WAVEGUIDES
AMPLIFIERS
ELECTRONIC EQUIPMENT
EQUIPMENT
FREQUENCY RANGE
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