E.E. Lysenko, S.V. Pankov, O.F. Pishko, V.G. Chumak, S.A. Churilova
The paper presents results of engineering of clinotrons - broadband sources of coherent oscillations, for the frequency range from
400 GHz to 500 GHz. The development of BWO O-type tubes with the output power above 20 mW for the frequency range from
400 GHz to 500 GHz is a challenging scientific and technical problem.
The corresponding problems of the physical nature related to а significant decrease of the interaction space, decrease of the efficiency of the energy extraction, increase of ohmic losses in the slow-wave structures were previously addressed in [10-13]. The presented paper describes a complex of technical and technological problems that had to be solved during engineering.
A technology of making of fine-scale slow-wave structures with a necessary shape and surface quality is described in the paper.
The electron gun which forms the electron beam having 0.1x2.5 mm2 cross-section and the current density of 80-100 A/cm2 has been updated and improved. Due to undertaken technical and design solutions, its reliability and the technological effectiveness have been increased, and the structure of the electron beam has been improved.
The effectiveness of the heat removal has been achieved by introducing of an expanded area of heat transfer in the cooling unit, which covers all surfaces heated by the electron beam. The metal melting near the collector has been avoided by introducing of a soldered wedge, which disperses the electron beam. A sector insert has been used in the output section the grating teeth.
A magnetic focusing system with the magnetic induction of 0.95 T in the center of the 31 mm clearance has been developed for the sub-millimeter wavelength clinotron by optimizing the design and its position in the magnetic clearance. The system has the weight of 10 kg.
Experimental samples of the clinotrons working in the frequency range from 400 GHz to 500 GHz have been developed. Working, starting, and service characteristics of a packed clinotron with the level of the output power from 20 mW to 100 mW and with a 8% frequency bandwidth are presented in this paper as well.