Experimental study on the stability of a compensated electron beam

The study of peculiarities of collective oscillations of a compensated electron beam in an electron cooling facility as well as the study of properties of the observed damping of the oscillations have been carried out. Electron beam formed in an electron gun, fixed in homogeneous magnetic fields, has been transported to the collector in the 7 cm aperture chamber. The experiments have been conducted at the electron energy 35 keV and current density up to 3 A/cm2 and energy 550 eV at current density up to 1.3 A/cm2. Vacuum in the facility varied in the range 10-6-10-10 Torr. The study of the beam dispersion properties has been performed according to the measurement of wave propagation which were oxcited by external electrodes. It is shown that at small quantity of secondary electrons a strong damping of both longitudinal and transverse oscillations occurs. The presence of the damping results in suppression of instabilities in the beam. In the experiments a compensated electron beam with current density, which exceeds by two orders the theoretical value of threshold of instability of axial-nonsymmetric oscillations is obtained. It is also shown that at the current