Abstract:
In the preferred application for preionizing TE lasers, in particular excimer lasers, the plasma X-ray tube (ER), which can also be referred to as single-chamber ion tube, has an elongated, box-shaped housing (G) including in its inside an also elongated cylindrical cathode (K) of generally U-shaped cross-section, the open end of which faces the X-ray target in the form of a gastight film. An elongated wire-shaped initiating electrode (11) is arranged between X-ray target (1) and cylindrical cathode (K). An electrical field is generated around the initiating electrode (11) by applying thereto a positive voltage or voltage pulse. The field thus generated forces the electrons which are present because of the ambient radiation to form long spiral paths, thus ionising gas atoms. Electron avalanches develop and initiate the wire discharge. Ions (i+) are extracted from the low-pressure plasma (3) by applying to the cylindrical cathode (K) a beam potential of typically between 60 kV and a maximum of 120 kV, and accelerated against the cylindrical cathode (K). On impact of the ions from the cylindrical cathode (K), secondary electrons are emitted and accelerated in the opposite direction, thus forming the electron beam (E), which on striking the X-ray target (1) creates the X-ray bremsstrahlung (X). Said plasma X-ray tube is also basically suitable as an electron gun: for this application, the film used as an electron window covering the window opening in the target holding wall need only be designed so as to be accordingly radiolucent to electron beams.
Abstract:
A surface discharge plasma cathode electron beam generating assembly (1) includes an anode (2) maintainable at a substantially constant first potential, a cathode device (3) having a first electrically conductive member (4), a dielectric member (5) at least partially surrounding the first member (4) and electrically conductive means (6) located on the outer surface of the dielectric member (5) and insulated therefrom. A capacitative divider circuit (7) is provided for maintaining the first electrically conductive member (4) at a second potential different from the first potential and for maintaining the electrically conductive means (6) at a high negative third potential relative to the first and second potentials.
Abstract:
A surface discharge plasma cathode electron beam generating assembly (1) includes an anode (2) maintainable at a substantially constant first potential, a cathode device (3) having a first electrically conductive member (4), a dielectric member (5) at least partially surrounding the first member (4) and electrically conductive means (6) located on the outer surface of the dielectric member (5) and insulated therefrom. A capacitative divider circuit (7) is provided for maintaining the first electrically conductive member (4) at a second potential different from the first potential and for maintaining the electrically conductive means (6) at a high negative third potential relative to the first and second potentials.
Abstract:
A pulsed plasma deposition device, comprising an apparatus for generating a beam of electrons (3), a target (4) and a substrate (6), the apparatus (3) being suitable for generating a pulsed beam of electrons directed towards said target (4) to determine the ablation of the material of said target (4) in the form of a plasma plume (19) directed towards said substrate (6); the device comprises a transportation and focussing group (13) of the beam of electrons towards said target (4), arranged between said apparatus (3) and said target (4) and comprising a transportation cone (14), the transportation and focussing group (13) also comprising a focussing electrode (15) directly connected to the transportation cone (14) and shaped substantially like a loop; the axis of symmetry (16) of the focussing electrode (15) is perpendicular, or substantially perpendicular, to the surface of the target (4).
Abstract:
The invention relates to a device for producing an electron beam, comprising a housing (12), which bounds a space (13) that can be evacuated and has an electron beam outlet opening; an inlet (16) for feeding a process gas into the space (13) that can be evacuated; a planar cathode (14) and an anode (15), which are arranged in the space (13) that can be evacuated and between which a glow-discharge plasma can be produced by means of an applied voltage, wherein ions can be accelerated from the glow-discharge plasma onto the surface of the cathode (14). The cathode has a first part (14a) made of a first material, which forms a centrally arranged first surface region of the cathode (14), and a second part (14b) made of a second material, which forms a second surface region of the cathode (14) that encloses the first surface region. The first material can be heated by the impingement with accelerated ions to a temperature at which electrons escape the first material predominantly due to thermionic emission.
Abstract:
Device (1) for generating plasma and for directing an flow of electrons towards a specific target (3); the device (1) comprises a hollow cathode (5); a main electrode (7) at least partially placed inside the cathode (5); a resistor (12), electrically earthing the main electrode (7); a substantially dielectric tubular element (21) extending through a wall (22) of the cathode; a ring-shaped anode (25) placed around the tubular element (21) and earthed; and an activation group (11) which is electrically connected to the cathode (5) and is able to reduce the electric potential of the cathode (5) of at least 8 kV in about 10 ns.