Obtaining linear electron beams by using the magnetron injection guns with cold secondary emission metallic cathodes (experiment)

Abstract

The problem of extending the life-time, of increasing the pulse and average power of many RF-sources is closely related to the design of their electron guns. As it is known, the magnetron injecting guns with secondary emission metallic cathodes (SEMIG) are specified by the high current emission density and long life-time. The main goal of these investigations is to determine the advantages and limitations of using SEMIGs as the electron source in high-power RF devices and accelerator injector systems. At this stage we have studied some questions concerning the operational beam stability, voltage and current increase. The experiments have been performed by using the experimental setup to investigate SEMIG linear electron beam parameters from single and multiple beams gun assemblies with the anode voltage up to 100 kV, pulse duration up to 10 /spl mu/s, repetition rate 50 Hz and 0.1-0.2 T magnetic field strength. Pulse-to-pulse long-term stability of the annular electron beams (internal diameter nearly equal to the cathode diameter, wide of ring 1-2 mm (wavelength of cyclotron oscillations)) with beam density up to 70 A/cm/sup 2/ have been achieved. It is shown, that the cathode diameter extension provides a proportionate increase of the beam current, and in the case of multiple beam gun assemblies we have separate identical electron beams with similar parameters of an single-beam gun.