Siemens Aktiengesellschaft

Volker Bruckner

Hans-Jurgen Cirkel

Dirk Friede

Willi Bette

Rudolf Baumgartl

A plasma X-ray tube, which can be referred to as a one-chamber ionizing tube for pre-ionizing TE lasers, in particular excimer lasers, includes an extended, box-like housing with a U-shaped hollow cathode which is disposed in the interior of the housing and is also elongated. The open side of the hollow electrode faces an X-ray target which is in the form of a gas-tight foil. Between the X-ray target and the hollow cathode is a long wire-shaped igniting electrode. When a positive voltage or a voltage pulse is applied to the igniting electrode, an electrical field is formed around it. Electrons that are present are forced onto a long, spiral path and gas atoms are ionized under the influence of the electrical field and because of ambient radiation. Electron avalanches form and lead to initiation of a wire discharge. When the accelerator voltage, which is typically at most between 60 kV and 120 kV, is applied to the hollow cathode low-pressure plasma, ions are extracted and accelerated against the hollow cathode. When the ions impact, secondary electrons are emitted from the hollow cathode and are accelerated in the opposite direction, so that an electron beam forms and strikes the X-ray target to generate X-ray retarding radiation. The plasma X-ray tube is fundamentally suitable as an electron gun, with a suitable electron-beam permeable configuration of a foil that covers the window opening in the target retaining wall and serves as an electron window.

Plasma X-ray tube, in particular for X-ray preionizing of gas lasers,

An excitation circuit for TE lasers serves to generate a homogeneous high pressure glow discharge between laser electrodes within a gas space of a laser chamber. A fast acting high voltage switch of a pulse forming network is a multi-channel pseudo-spark switch and is preferably integrated with the laser. The switch is formed of a parallel circuit including a number of individual pseudo-spark switches with gaps. The total multi-channel pseudo-spark switch is filled with an ionizable low pressure gas filling at a given pressure. Voltage is applied to the anode and the cathode in such a way that the resulting gas discharge is located on the left-hand branch of the Paschen curve. The switch of the excitation circuit can also be used as a separate structural element for triggering an electrical high voltage switch circuit, and also for so-called flat plane laser systems.

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Mombris, Germany

Volker Bruckner