Özet:

In this paper, we measured the breakdown curves of a dc glow discharge with hollow cathode and flat electrodes. It is shown that at low gas pressure (p ≤ 0.05 Torr), the left branches of the breakdown curves for the hollow cathode and the flat electrodes are identical. At high gas pressures (p ³ 0.3 Torr), the right branch of the breakdown curve of the discharge with a hollow cathode is close to the breakdown curve for the distance between the plane electrodes, equal to the gap between the edge of the plates of the hollow cathode and flat anode. Current-voltage characteristics of the hollow cathode discharge were measured. It is shown that with low gas pressure p < 0.1 Torr discharge is in the high-voltage (electron beam) form with ascending current-voltage characteristic, when secondary electrons are accelerated along electric field lines and form an electron beam. In the gas pressure range p ≥ 0.1 Torr the discharge at low current burns in the glow mode, in which the discharge glow is practically absent in the cavity between the plates of the cathode, and the current-voltage characteristic of the discharge is ascending. At higher current the discharge goes into the hollow cathode mode, filling the space between the plates, and it has an almost vertical current-voltage characteristic. The transition from a glow discharge mode into a hollow one possesses a hysteresis. At gas pressures p ~ 1 Torr the hollow cathode effect disappears, since the thickness of the cathode layer is small compared with the gap between the plates of the cathode. It is shown that when the collectors are placed on the anode across the gap between the plates of the hollow cathode, the radial profile of the electron current to the anode in the mode of electron beam has a sharp maximum at the axis of the discharge chamber. The profile is flatter if the chain of collectors on the anode is directed along the cavity of the cathode. Increasing the gas pressure leads to a strong scattering of the electron beam, and the radial profiles of electron current to the anode are approximately the same in both transverse directions in the glow mode as well as in the hollow cathode one.

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