Kraftwerk Union Aktiengesellschaft

Siemens Aktiengesellschaft

Hans-Jurgen Cirkel

Willi Bette

Reinhard Muller

Dirk Friede

Volker Bruckner

Rudolf Baumgartl

Elmar Muller-Horsche

MuReinhard

Preionization is important for the generation of a homogeneous glow discharge in the gas space of a laser chamber between laser electrodes. TE type excimer lasers operate especially with X-ray preionization, for which high voltage pulses are needed. According to the present invention, the voltage pulses are obtained by means of an auxiliary circuit that includes a branch which is connected in parallel with a high voltage switch or with the laser discharge gap and which incorporates a saturable magnetic inductance and the primary winding of a high voltage pulse transformer connected in series therewith. The high voltage triggering pulses for the preionization element, which is an X-ray tube in particular, are generated in the secondary winding of the transformer. If the branch is connected in parallel with the high voltage switch it also has a series capacitor. If it is in parallel with the laser discharge gap then the branch has a shunt capacitor. In this way, the timing of the preionization and in particular the X-ray pulse, can be adjusted precisely in relation to the voltage rise time through the laser electrodes and in relation to the laser.

Device for pre-ionization in discharge-pumped gas lasers, in particular

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.

Multichannel pseudo-spark switch and excitation circuit for gas lasers

A high-energy TE laser system, includes an excitation circuit, a laser head having an optical axis, a laser chamber with a gas space formed therein, at least two laser electrodes being disposed opposite each other and spaced apart in the laser chamber parallel to the optical axis of the laser head for producing an arc-free capacitor discharge between the electrodes being as homogenous as possible in the gas space for excitation, at least one rapid high-voltage switch, a pulse-forming network connected to the rapid high-voltage switch for producing high-voltage pulses at the laser electrodes with the rapid high-voltage switch, the pulse-forming network including first and second strip conductor capacitors respectively associated with the rapid high-voltage switch and with the laser head, the strip conductor capacitors including plates and dielectric layers disposed between the plates extended substantially normal to the optical axis of the laser head, forming a capacitor stack stacked substantially parallel to the optical axis of the laser head, the plates being connected in the pulse-forming network, the pulse-forming network being a Blumlein circuit in which at least one plate of the second strip conductor capacitor is connected to one of the laser electrodes, and the plates being divided into n adjacent plate sections having n-1 partings respectively disposed therebetween, and coupling inductances conductively connecting the plate sections to each other. Otherwise, the pulse-forming network is a charge-transfer circuit in which at least a partial surface of the plates of the first and second strip conductor capacitors are connected in common to one of the laser electrodes.

High-energy laser system

A high-power pulse transformer for short, high-voltage and/or high-current pulses includes:

High-power pulse transformer for short high-voltage and/or high-current

A high-energy TE laser system, includes an excitation circuit having supply lines, a laser head having an optical axis, a laser chamber with a gas space formed therein, at least two laser electrodes being disposed opposite each other and spaced apart in the laser chamber parallel to the optical axis of the laser head for producing an arc-free capacitor discharge between the electrodes being as homogeneous as possible in the gas space for excitation, at least one rapid high-voltage switch, a pulse-forming network connected to the rapid high-voltage switch for producing high-voltage pulses at the laser electrodes with the rapid high-voltage switch, the pulse-forming network including first and second strip conductor capacitors respectively associated with the rapid high-voltage switch and with the laser head, and the pulse-forming network including first and second equivalent inductances of the excitation circuit formed of self-inductances of the high-voltage switch, the laser head, the supply lines of the excitation circuit and the strip conductor capacitors, the pulse-forming network being a Blumlein circuit for a given maximum build-up time of the high-voltage pulses produced at the laser electrodes, the first strip conductor capacitor having a capacitance being less than the capacitance of the second strip conductor capacitor by a factor k&lt;1, and the first equivalent inductance being connected in series with the first strip conductor capacitor and having an inductance being greater than the inductance of the second equivalent inductance by a factor .sup.1 /k. The pulse-forming network may also be a charge transfer circuit.

High-energy TE laser system

An excitation system for generating a fast pulsed high-voltage discharge into a load, especially for exciting a high-power laser, by an arc-free capacitor discharge which is as homogeneous as possible. The system includes a laser chamber wherein two laser electrodes are oppositely located and spaced from one another, and extending parallel to an optical axis of the laser chamber; and a high voltage supply unit; a pulse forming network which further includes, in a shunt branch connected in series with the stripline capacitors, at least one fast high-voltage switching element, which, due to its activation the high-voltage pulses are generated at the laser electrodes. The fast high-voltage switching element is formed as a saturable magnetic reactor having a magnetizing current which makes the reactor go into saturation if the charging voltage at the stripline capacitors has come into the vicinity of the peak thereof, and wherein the shunt branch of the laser chamber includes a series circuit containing a respective stripline capacitor and the laser chamber itself.

Excitation system for generating a fast pulsed high-voltage discharge,

An excitation circuit for laser systems with excitation by a maximally homogeneous, arc-free capacitor discharge in a gas space of a laser head between at least two mutually spaced-apart laser electrodes includes at least one fast acting high-voltage switch activatable via a pulse-forming network connected thereto for generating high-voltage pulses at the laser electrodes; first and second stripline capacitors and appertaining equivalent inductances operatively associated with the pulse-forming network and the high-voltage switch and the laser head; preionization devices operatively connected to the laser electrodes and having a plurality of members of at least one of surface discharge gap members and preionization rod members, together with auxiliary circuit connected thereto, the auxiliary circuits being connected to the pulse-forming network for providing all auxiliary voltages and currents for operating the preionization devices, the auxiliary circuits being connectible, in addition to ground potential of the excitation circuit, to at least one of three discrete circuit points of which one point is connected to a high-voltage input of the pulse-forming network, a second point is connected to a high-voltage branching point of the high-voltage switch and one of the stripline capacitors, and a third point is connected directly to the laser electrode having high potential, for controlling the instant of onset of the laser gas discharge and the time relationship between applying a high-voltage pulse to the laser electrodes, on the one hand, and applying a firing pulse to poles of the preionization devices, on the other hand.

Excitation circuit for laser systems, especially for TE-high energy

An excitation circuit for a TE high-energy laser system, includes at least one high-speed, high-voltage switch, activatable for energizing a pulse-generating network to generate high-voltage pulses at a pair of laser electrodes; the pulse generating network having first and second strip-line capacitors associated with the high-voltage switch and the laser chamber and with appertaining equivalent inductances of the excitation circuit formed from self-inductance of the high-voltage switch, the laser chamber, leads of the system and the stripline capacitors has at least a third stripline capacitor included in the pulse-generating network in addition to the first and second stripline capacitors, a series connection of the high-voltage switch and one of the equivalent inductances being connected in parallel with the first stripline capacitor and with a series-parallel circuit formed of the second stripline capacitor and a parallel connection made up of the third stripline capacitor in parallel with an impedance as well as with a series connection of the laser chamber and another of the equivalent inductances.

Excitation circuit for a TE high-energy laser system

Laser of the TE type, including a gas-tight housing defining a laser chamber having a gas space, at least two laser electrodes disposed parallel to the optical axis of the laser within the housing, the electrodes being disposed mutually opposite and at a given distance from each other, excitation of the laser being provided by an arc-free capacitor discharge being as homogeneous as possible in the gas space between the electrodes, a pre-ionization device disposed within the housing, current leads and a current return disposed in the housing, each of the electrodes being connected to one of the current leads and current return, a device disposed in the laser chamber for conducting laser gas therethrough, a pulse-forming network having a capacitor contact surface and being connected to the current leads and current returns, the laser electrodes being in the form of at least two subelectrodes facing toward the pulse-forming network and subelectrodes facing away from the pulse-forming network, an electrode bridge connected to the subelectrodes facing away from the pulse-forming network, the subelectrodes of opposite electrodes defining subdischarge spaces therebetween and a subelectrode space between the subdischarge spaces, and insulation jackets disposed on the current leads, the current leads being extended in an insulated manner from the electrode bridge through the subelectrode space, through the current return and to the capacitor contact surface.

Laser of the TE type, especially a high-energy laser

Sheetform conductor type capacitor for energy storage in combination with a high-energy laser of the TE type, the laser having an optical axis, a laser chamber with at least two laser electrodes having a gas space therebetween, the laser electrodes being spaced apart opposite each other and extended parallel to the optical axis, excitation taking place by an arc-free capacitor discharge in the gas space being as homogeneous as possible, and pre-ionization devices associated with the laser electrodes, a pulse forming network, connected to the laser electrodes, coatings of the sheetform conductor type capacitor connected to the laser electrodes, electrodes defining a fast-high-voltage contact-break distance, the contact-break electrodes being connected to the laser electrodes, dielectric layers disposed between the coating of the sheetform conductor type capacitor in a direction substantially normal to a given stacking direction thereto parallel to the optical axis of the laser, the at least two laser electrodes including a first electrode connected through the sheetform conductor type capacitor to the pulse-forming network for a high voltage pulse, and a second electrode being disposed opposite the first electrode being connected to ground potential, wherein the improvement comprises at least one of the sheetform conductor type capacitors connected to the first laser electrode having notches formed therein for increasing the length of their current path for discharge current.

Microstrip capacitor for energy storage, preferably for high-energy

Excitation system for fast pulsed discharge with excitation by a highly homogeneous arc-free capacitor-discharge in a gas space between and defined by at least two electrodes of a laser chamber, the two electrodes being spaced from one another and extending parallel to the optical axis of the laser, and with first and second stripline capacitors for induction-free energy-storage and for contacting the laser electrodes and electrodes of a fast high-voltage switching gap associated therewith, respectively, includes a plurality of electrodes forming part of the first and the second stripline capacitors, a plurality of dielectric layers disposed between the capacitor electrodes, the dielectric layers and the capacitor electrodes extending substantially normally to the optical axis of the laser and being stacked substantially parallel to the optical axis of the laser in a capacitor stack, and laterally extending connecting lugs connecting the capacitor electrodes to the electrodes of the laser chamber.

Excitation system for a fast pulsed discharge

High-energy laser excitable by an arc-free capacitor discharge includes a power capacitor with minimal self-inductance formed of a stack of metal layers mutually superimposed perpendicularly to a given axis, with respective layers of insulation disposed between mutually adjacent metal layers of the stack, the metal layers and the insulation layers being formed with mutually aligned cut-outs in vicinity of the given axis so as to form a free space within the stack, respective surface portions of alternating layers of the metal layers projecting into the free space above one another as electrodes of given common polarity, the surface portions of the metal layers of respective opposite common polarity being disposed symmetrically with respect to the given axis in the free space; and a laser tube formed with a discharge chamber and having discharge electrodes, the laser tube being disposed in the free space of the power capacitor, the electrodes of given common polarity of the power capacitor being connected to the discharge chamber of the laser tube.

High-energy laser

Power capacitor with minimal self-inductance includes a stack of metal layers mutually superimposed perpendicularly to a given axis, with respective layers of insulation disposed between mutually adjacent metal layers of the stack, the metal layers and the insulation layers being formed with mutually aligned cut-outs in vicinity of the given axis so as to form a free space within the stack, respective surface portions of alternating layers of the metal layers projecting into the free space above one another as electrodes of given common polarity, the surface portions of the metal layers of respective opposite common polarity being disposed symmetrically with respect to the given axis in the free space.

Growing community of inventors

Erlangen, Germany

Hans-Jurgen Cirkel