Triode Electron Gun of the LUE-200 Linear Accelerator, IREN Facility of the Laboratory of Neutron Physics, Joint Institute for Nuclear Research

The electron injector (electron gun (EG)) is a triode system (cathode–control grid–anode with a second grid “wall”) with a grounded anode and an isolated filament shielded cathode supplied with a high-voltage (up to –240 kV) pulse from the thyratron modulator through a pulse transformer. The composition of the main systems is as follows: (1) triode gun, (2) pulse modulator of the gun, (3) pulse transformer, and (4) the equipment of the stand (high-voltage pulsed charging modulator, synchronizer with startup system, DC sources, vacuum equipment, power systems of control and monitoring, and focusing system). The triode gun is an electron injector with a heated oxide-barium cathode and a controlled startup on the grid of the cathode–grid node from the GS-34 microwave tube. The modulator consists of PFN of 380 pF capacitors with a total capacity of 12 nF with inductors of 0.66 µH composing a double forming line. The PFN charging is supplied from the high voltage source of TDK Lambda. Starting the grid with an adjustable delay to adjust the pulse duration from 40 to 400 ns of the beam injected from the cathode is done from the starting pulse of the cathode node from the first channel of the synchronizer. The thyratron modulator is launched from the second channel. As a result of adjustment, a beam with a current pulse of 5 A at focusing current 3.1 A of ML1 focusing solenoid at voltage 200–220 kV with a beam with a diameter of 5 mm at a frequency of 25 Hz is obtained. To switch to a frequency of 50 Hz, the current of the focusing solenoid is reduced to 1.5 A. In this case, the beam diameter increases to 1 cm. A stable mode of operation of the electron source is recorded for several tens of shifts.