CLINOTRON AS A FREQUENCY MULTIPLIER IN THE SUB-MM WAVEBAND (λ= 0.935 mm)

In comparison to backward wave oscillator (BWO) of O-type, requirements to the quality of electron beams are weakened in the frequency multipliers. Therefore, frequency multipliers may have a considerable perspective for mastering the sub-millimetre waveband, although, their output power is usually less than in the BWOs of the comparable waveband. Experimental works on the frequency multipliers are known in the millimetre waveband. In those devices, a resonator of klystron type, fed by an external power oscillator of the centimetre waveband, serves as the buncher section. The slow-wave structure of the comb type operates in the power-catching regime. We are certain that for the sub-millimetre waveband it may be possible to design a multiplier as a two-cascade clinotron-oscillator, which  is simultaneously a modulating generator, a buncher, and a power-catcher. Numeral simulations showed that in the clinotron there exists the effect of “layer-by-layer” bunching of electrons in a sheet beam: the farther an electron layer is located from the surface of the comb, the later electron bunching in that layer occurs. In a remote layer, electrons form bunches outside the comb of the modulating part of the clinotron. Therefore, clinotron can be used as an electron beam buncher. The aim of the present work was an experimental verification of this possibility. In the paper, a simple design of a clinotron-multiplier is introduced, and the results of investigation of its operation are presented. In the buncher section of the clinotron, oscillations are generated with the wavelength of 2.8 mm. In the power-catcher section, a signal is generated with the wavelength of 0.935 mm. We also demonstrate the possible decrease in the magnetic field induction of the focusing (guide) magnetic field to 0.5÷0.3 T in this device, while for a BWO of the same waveband the necessary guide magnetic field is about 1.0 T.