Generating microwave radiation

1. A method for operating a device having an anode and a cathode for generating microwave radiation with an accelerating voltage, a chronological sequence of the accelerating voltage being provided by a sequence of voltage pulses, the method comprising:

applying a first voltage pulse with an operating amplitude between the anode and the cathode;

determining whether an electric flashover occurs during the applied first voltage pulse; and

applying a second voltage pulse following the first voltage pulse with a deionization amplitude that is smaller than the operating amplitude when the electric flashover occurs during the applied first voltage pulse.

2. The method as claimed in claim 1 , further comprising waiting a deionization period before the application of the second voltage pulse when the electric flashover occurs.

3. The method as claimed in claim 1 , further comprising:

applying at least one additional first voltage pulse with the operating amplitude before the application of the second voltage pulse; and

counting of the applied first voltage pulses between the anode and the cathode, in which the electric flashover occurs,

wherein applying the second voltage pulse comprises applying the second voltage pulse when the number of applied first voltage pulses in which the flashover occurs exceeds a predetermined number.

4. The method as claimed in claim 3 , further comprising resetting the number of applied first voltage pulses in which the electric flashover occurs when after a first voltage pulse in which the electric flashover occurred, a predetermined flashover-free period elapses.

5. The method as claimed in claim 1 , further comprising:

determining whether an electric flashover occurs during the applied second voltage pulse;

reducing a deionization amplitude when the electric flashover occurs during the applied second voltage pulse; and

applying the second voltage pulse with the reduced deionization amplitude between the anode and the cathode.

6. The method as claimed in claim 5 , further comprising repeating the reduction of the deionization amplitude and the application of the second voltage pulse with the reduced deionization amplitude between the anode and the cathode when the electric flashover occurs during the applied second voltage pulse with the reduced deionization amplitude.

7. The method as claimed in claim 5 , further comprising determining a fault when a value of the reduced deionization amplitude falls below a predetermined value.

8. The method as claimed in claim 1 , further comprising generating the accelerating voltage with a multilevel converter connected between the anode and the cathode, and

wherein the multilevel converter comprises a plurality of energy storage devices that are cascadable and are connectable in series between the anode and the cathode.

9. The method as claimed in claim 8 , further comprising:

connecting, in series, a first group of the energy storage devices of the plurality of energy storage devices for the generation of the first voltage pulse; and

connecting, in series, a second group of the energy storage devices of the plurality of energy storage devices for the generation of the second voltage pulse,

wherein the number of the first group of energy storage devices is selected so as to be greater than the number of the second group of energy storage devices.

10. The method as claimed in claim 2 , further comprising:

applying at least one additional first voltage pulse with the operating amplitude before the application of the second voltage pulse; and

counting of the applied first voltage pulses between the anode and the cathode, in which the electric flashover occurs,

wherein applying the second voltage pulse comprises applying the second voltage pulse when the number of applied first voltage pulses in which the flashover occurs exceeds a predetermined number.

11. The method as claimed in claim 10 , further comprising resetting the number of applied first voltage pulses in which the electric flashover occurs when, after a first voltage pulse in which the electric flashover occurred, a predetermined flashover-free period elapses.

12. The method as claimed in claim 4 , further comprising:

determining whether an electric flashover occurs during the applied second voltage pulse;

reducing a deionization amplitude when the electric flashover occurs during the applied second voltage pulse; and

applying the second voltage pulse with the reduced deionization amplitude between the anode and the cathode.

13. The method as claimed in claim 12 , further comprising repeating the reduction of the deionization amplitude and the application of the second voltage pulse with the reduced deionization amplitude between the anode and the cathode when the electric flashover occurs during the applied second voltage pulse with the reduced deionization amplitude.

14. The method as claimed in claim 6 , further comprising determining a fault when a value of the reduced deionization amplitude falls below a predetermined value.

15. The method as claimed in claim 2 , further comprising generating the accelerating voltage with a multilevel converter connected between the anode and the cathode, and

wherein the multilevel converter comprises a plurality of energy storage devices that are cascadable and are connectable in series between the anode and the cathode.

16. An appliance for operating a device having an anode and a cathode for generating microwave radiation with an accelerating voltage, a chronological sequence of the accelerating voltage being provided by a sequence of voltage pulses,

wherein the appliance is configured to:

apply a first voltage pulse with an operating amplitude between the anode and the cathode;

determine whether an electric flashover occurs during the applied first voltage pulse; and

apply a second voltage pulse following the first voltage pulse with a deionization amplitude that is smaller than the operating amplitude when the electric flashover occurs during the applied first voltage pulse.

17. An arrangement comprising:

a device operable to generate microwave radiation, the device comprising an anode and a cathode; and

an appliance operable to generate an accelerating voltage between the anode and the cathode, a chronological sequence of the accelerating voltage being provided by a sequence of voltage pulses,

wherein the appliance is configured to:

apply a first voltage pulse with an operating amplitude between the anode and the cathode;

determine whether an electric flashover occurs during the applied first voltage pulse; and

apply a second voltage pulse following the first voltage pulse with a deionization amplitude that is smaller than the operating amplitude when the electric flashover occurs during the applied first voltage pulse.

18. The arrangement as claimed in claim 17 , further comprising a Marx modulator as a multilevel converter.

19. A therapy, fluoroscopic or irradiation device comprising:

an arrangement operable to generate microwave radiation, the arrangement comprising:

a device operable to generate the microwave radiation, the device comprising an anode and a cathode; and

an appliance operable to generate an accelerating voltage between the anode and the cathode, a chronological sequence of the accelerating voltage being provided by a sequence of voltage pulses,

wherein the appliance is configured to:

apply a first voltage pulse with an operating amplitude between the anode and the cathode;

determine whether an electric flashover occurs during the applied first voltage pulse; and

apply a second voltage pulse following the first voltage pulse with a deionization amplitude that is smaller than the operating amplitude when the electric flashover occurs during the applied first voltage pulse.

20. The therapy, fluoroscopic or irradiation device as claimed in claim 19 , further comprising a Marx modulator as a multilevel converter.