Efficient operation of a high-powerX-band gyroklystron

Abstract

Experimental studies of amplification in a two-cavity X-band gyroklystron are reported. The system utilizes a thermionic magnetron injection gun at voltages up to 440 kV and currents up Our present efI'ort to increase gyroklystron power levels has focused on two issues. The first involves increasing the beam voltage above conventional (long pulse) levels as described in previous design papers [11,12] [14]. In this paper, we briefly describe the experimental configuration, discuss the microwave diagnostics, and present optimal twocavity gyroklystron performance.Details of the experimental setup, tube stability, and flat-field amplifier experiments that achieved peak powers of 2.7 MW appear elsewhere [15].A schematic of the overall system is shown in Fig. 1(a). A 1.5-ps, 500-kV, 400-A line-type modulator provides the required voltages to the MIG. Eight water-

High power operation of a K-band second harmonic gyroklystron

“…Furthermore, the relative sensitivity o the output power to changes in beam current is over times larger in the second-harmonic tube [9]. In terms of the ratio of peak power to output wavelength squared (an index derived from scaling laws), the relative power performance is over a factor of 3.5 times larger than the previous fundamenta1 mode tubes and is comparable to the best results from klystrons [31.…”

“…A magnetron injection gun produces a 440 kV, 200-24S A, 1 ps beam with an average perpendicular-to-parallel velocity ratio slightly less than 1. The TED» input cavity is driven near 9.88 6Hz and the TE02& output cavity resonates near 19.76 6Hz. Peak powers exceeding 21 MW are achieved with an e%ciency near 21% and a large signal gain above 2S dB.…”

“…The final potential drawback is the large power required to supply the applied magnetic field. Actually, the required field strength of both high power gyroklystrons and klystrons for collider applications are similar [3,9]. This problem can be eliminated with superconducting magnets or alleviated by operating at a harmonic of the cyclotron frequency.…”

“…A magnetron injection gun produces a 440 kV, 200-24S A, 1 ps beam with an average perpendicular-to-parallel velocity ratio slightly less than 1. The TED» input cavity is driven near 9.88 6Hz and the TE02& [3,9]. This problem can be eliminated with superconducting magnets or alleviated by operating at a harmonic of the cyclotron frequency.…”

“…Because there are no sources that currently satisfy all these criteria, considerable research has been undertaken in the past few years to enhance the performance of existing amplifier technology. Configurations which are under investigation include conventional klystrons [3], relativistic klystrons [4], free-electron lasers [5], intense-beam traveling wave tubes [6], magnicons [7], CARMs (cyclotron auto-resonance masers) [8], and gyroklystrons [9].…”