Technique for measuring boundaries of electron beam instability regions

A technique for measuring boundaries of electron beam instability regions is developed to investigate electrostatic instability of an electron gun beam when the characteristic of instability is a hysteresis dependence of the current passing through the electron-optical system on the input current. The technique for measuring the width of the current hysteresis loop and the bounda--ries of instability regions is based on excitation of oscillations of the LC circuit included into the circuit of one of the electron gun electrodes. When the beam is instable the harmonic beam current oscillations caused by resonance excitation of the LC circuit are observed. The scheme of the measuring device and the current time dependencies for the collector circuit are given. The given technique has a higher sensibility and resolution