Experimental proof-of-principle demonstration of sub-MM clinotron-multiplier

We demonstrate experimentally a possibility of triple frequency multiplication in a simple CW clinotron (a BWO with inclined beam) oscillator. In the proof-of-principle experiment the device generated λ_b ≈ 2.8 mm (107 GHz) in the buncher section while in the catcher section 10 mW at λ_c ≈ 0.935 mm (321 GHz) were measured. The principal ability of a clinotron-type oscillator to pre-bunch a layer of the electron beam capable of production of terahertz radiation in the short-wavelength part of sub-millimetre waveband is shown.