Efficient Low-Voltage Operation of a CW Gyrotron Oscillator at 233 GHz.
The gyrotron oscillator is a source of high average power millimeter-wave through terahertz radiation. In this paper, we report low beam power and high-efficiency operation of a tunable gyrotron oscillator at 233 GHz. The low-voltage operating mode provides a path to further miniaturization of the gyrotron through reduction in the size of the electron gun, power supply, collector, and cooling system, which will benefit industrial and scientific applications requiring portability. Detailed studies of low-voltage operation in the TE(2) (,) (3) (,) (1) mode reveal that the mode can be excited with less than 7 W of beam power at 3.5 kV. During CW operation with 3.5-kV beam voltage and 50-mA beam current, the gyrotron generates 12 W of RF power at 233.2 GHz. The EGUN electron optics code describes the low-voltage operation of the electron gun. Using gun-operating parameters derived from EGUN simulations, we show that a linear theory adequately predicts the low experimental starting currents.
M. K. Hornstein was with the Department of Electrical Engineering and Computer Science and the Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 USA. She is now with the Naval Research Laboratory, Washington, DC 20375 USA. V. S. Bajaj and R. G. Griffin are with the Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139 USA. R. J. Temkin is with the Department of Physics and the Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
Melissa K
MK
Hornstein
Vikram S
VS
Bajaj
Robert G
RG
Griffin
Richard J
RJ
Temkin