Patent Number: 
Section: claims

1. A device for generating extreme ultraviolet radiation and soft x-ray radiation with a gas discharge operated on the left branch of the Paschen curve, the device comprising:a discharge chamber (10) of a predetermined gas pressure;two electrodes (11, 12) arranged in the discharge chamber (10), wherein the two electrodes have an opening (14, 15), respectively, wherein the openings have coinciding symmetry axes (13);wherein the two electrodes, in the course of a voltage increase (16) upon reaching a predetermined ignition voltage (Uz), generate a plasma (17) located in the area between the openings (14, 15);a triggering electrode (19) arranged in a space (23) adjoining a first one of the electrodes (11), wherein the triggering electrode triggers an ignition of the plasma (17) for producing the radiation (17′) by gas discharge;an energy storage device for supplying stored energy into the plasma (17) with the two electrodes (11, 12);wherein the triggering electrode (19) is arranged outside of a particle beam being formed on the symmetry axes (13) or is provided with a shielding (35) preventing the particle beam from impinging on the triggering electrode (19). 2. The device according to claim 1, wherein the triggering electrode (19) is arranged on the symmetry axes of the openings (14, 15) of the electrodes (11, 12), wherein the shielding is an insulator provided on an end face (34) of the triggering electrode facing the openings (14, 15) of the electrodes. 3. The device according to claim 2, wherein the insulator is a layer applied onto the end face (34) of the triggering electrode (19). 4. The device according to claim 2, wherein the insulator is a member that is sunk into the end face (34) of the triggering electrode (19). 5. The device according to claim 4, wherein the insulator has a recess (36) with a cross-section matched to the particle beam. 6. The device according to claim 5, wherein the recess (36) of the insulator tapers conically. 7. The device according to claim 1, wherein the triggering electrode (19) is completely insulated at least relative to the space (23) adjoining the first electrode (11). 8. The device according to claim 7, wherein the shielding (35) of the triggering electrode (19) has a residual conductivity that dissipates surface charges but prevents a discharge-affecting current flow between a second one of the two electrodes (12) and the triggering electrode (19). 9. The device according to claim 8, wherein the triggering electrode (19) is formed as a hollow cylinder surrounding the symmetry axes. 10. The device according to claim 9, wherein the triggering electrode (19) has a bottom that is facing away from the two electrodes (11, 12), wherein the bottom is embodied as an insulator or is embodied as a metal bottom connected to the potential of one of the electrodes (11, 12) and insulated relative to a remaining part of the triggering electrode (19). 11. The device according to claim 1, wherein the triggering electrode (19) is an annular plate mounted transversely to the symmetry axis (13) of the electrodes (11, 12) in the first electrode (11) or the triggering electrode is at least one electrode pin mounted transversely to the symmetry axis (13) of the electrodes (11, 12) in the first electrode (11). 12. The device according to claim 1, wherein the triggering electrode (19) is mounted in a first one of the electrodes (11) and is insulated relative to the first electrode. 13. The device according to claim 1, wherein the shielding (35) is comprised of a temperature-resistant insulation material. 14. The device according to claim 1, wherein the shielding (35) is connected to the triggering electrode (19) so as to provide excellent thermal conducting. 15. The device according to claim 1, wherein the shielding (35) has a diameter matching at least a diameter of the openings (14, 15) of the two electrodes.