Calculation of a cathode unit with ring emitters

To increase the electron current in an electron gun with a hole on the axis the calculation of a cathode unit is carried out. The cathode unit consists of 10 cathodes in the form of a tungsten ring of a rectangular cross section of the 1 mm thickness, internal and external diameters of 16 and 20 mm, respectively. It is shown that at the 2400 K tungsten cathode temperature, j=0.2 A/cm2 emission current density and ω/j=288 V parameter, where ω is power emitted by the cathode, the emission cathode current is 0.24 A and voltage between the adjacent cathodes is 860 V. The schematic diagram of the cathode unit supply system are given. The system ensures s nchronization of the high-voltage extending pulse with the voltage peaks on the cathodes. The calculation results have shown that the given method of current increasing in electron guns with the limited transverse dimensions can be realized without any difficulties