Optimized high-temperature cathode-heater unit

In electrophysical apparatus and accelerators that form electron beams with a high current density, the most stringent requirements are imposed on the operating life, reliability, and thermal efficiency of the high-temperature cathode-heater units (CHU), the replacement of which involves great expenditures of time and prolonged shutdown of the apparatus. The shortcomings of existing CHUs with LaB6 emitters include, among others, the low optical transparency of the graphite heating element and inconstancy of the temperature field of the emitter owing to unavoidable thickening at the locations of the massive leads. All of this reduces the thermal efficiency of the CHU. The authors describe a CHU that is free of the above-mentioned shortcomings. The CHU has a thermal efficiency of > 80% and a temperature inconstancy ΔT < 5 K. the heater power of the cathode unit, which has an emitter area of 20 cm2, at temperature T = 2,050 K is < 1 kW, and the operating life is >700 h