Abstract A glow discharge device comprising an enclosure and means to maintain a suitable gas in the enclosure at a predetermined pressure. An electrode arrangement is either at least partly disposed within the enclosure or forms part of a wall of the enclosure. The electrode arrangement includes one or more anodes, a cathode, and a control electrode. Power supply means are provided to apply a electrical potentials to the anode or anodes said cathode and said control electrode to maintain a first potential difference between an anode and said cathode to generate a first glow discharge, and to maintain a second potential difference between an anode and said control electrode to generate a second glow discharge. The combined first and second glow discharges produces a beam of charged particles, the power intensity of which is controlled by varying the potential applied to the control electrode to vary the glow discharge independently of the potential applied to the cathode.
In a glow discharge device of the type in which an electron beam is produced by secondary electron emission from a surface of the cathode as the result of ion bombardment of the cathode, having an enclosure for containing an ionizable gas at a predetermined pressure, an anode, a cathode spaced from said anode, means for applying an electrical potential difference between said anode and cathode to ionize said gas and maintain a glow discharge, the improvement comprising a hollow control electrode of substantially annular shape having an open channel shaped cross-section facing inwardly, means for applying an electrical potential difference between the anode and said control electrode to further ionize said gas in the enclosure to a level at which the electron beam is produced by secondary emission from the cathode, said hollow control electrode being positioned where the electron beam emitted by the cathode passes through the hollow electrode.
Claim 2
Dependent Claim
151 words
In a glow discharge device of the type in which an electron beam is produced by secondary electron emission from a surface of the cathode as the result of ion bombardment of the cathode, having an enclosure for containing an ionizable gas at a predetermined pressure, an anode, a cathode spaced from said anode, means for applying an electrical potential difference between said anode and cathode to ionize said gas and maintain a glow discharge, the improvement comprising a hollow control electrode of substantially annular shape having an open channel shaped cross-section facing inwardly, means for applying an electrical potential difference between the anode and said control electrode to further ionize said gas in the enclosure to a level at which the electron beam is produced by secondary emission from the cathode, said hollow control electrode being positioned where the electron beam emitted by the cathode passes through the hollow electrode.
Claim 3
Dependent Claim
56 words
A device according to claim 1 wherein a sensing means is provided to obtain a signal indicative of the current flowing in the said electron beam and means are provided to use said signal to vary the potential applied to the control electrode in response to said signal to modulate the power intensity of the beam.