Electron gun and radiation generating apparatus
The invention relates to an electron gun for generating a flat electron beam, comprising a cathode with an emission surface which is curved about a central axis and which is designed to emit electrons. The electron gun further comprises an accelerating device for accelerating the electrons in a radial direction towards a target region on the central axis. Furthermore, the emission surface has a width in the azimuth direction and a height oriented perpendicularly to the width, said width being at least ten times greater than the height.
1. An electron gun for generating a flat electron beam, the electron gun comprising:
a cathode comprising an emission surface that is curved about a central axis and is configured to emit electrons; and
an accelerator operable to accelerate the electrons in a radial direction toward a target region on the central axis,
wherein the emission surface has a width in an azimuthal direction, and the emission surface has a height oriented perpendicularly to the width, and
wherein the width is at least ten times the magnitude of the height.
2. The electron gun of claim 1 , wherein the accelerator is configured to deflect the electrons in a thickness direction oriented perpendicularly to a beam direction and perpendicularly to a width direction.
3. The electron gun of claim 2 , wherein the accelerator is configured to focus a flat electron beam in the thickness direction.
4. The electron gun of claim 1 , wherein the width of the emission surface is at least one hundred times greater than the height of the emission surface.
5. The electron gun of claim 4 , wherein the width of the emission surface is at least one thousand times greater than the height of the emission surface.
6. The electron gun of claim 1 , wherein the emission surface of the cathode is configured as a closed ring.
7. The electron gun of claim 1 , wherein a beam direction in the target region does not point toward the emission surface of the cathode.
8. The electron gun of claim 1 , wherein a beam direction at a location of the cathode is not perpendicular to the central axis.
9. The electron gun of claim 1 , wherein a beam direction in the target region is not perpendicular to the central axis.
10. The electron gun of claim 1 , wherein an edge surface of an electrode of the accelerator is configured as a segment of a surface of revolution with an axis of the rotation that is oriented parallel to the central axis.
11. The electron gun of claim 10 , wherein the surface of revolution segment of the edge surface has a rotation angle of three hundred and sixty degrees.
12. The electron gun of claim 1 , wherein the accelerator comprises a magnetic field generator.
13. The electron gun of claim 12 , wherein the magnetic field generator is configured to generate a magnetic field configured to be rotationally symmetrical about an axis parallel to the central axis.
14. A radiation generating apparatus comprising:
an electron gun for generating a flat electron beam, the electron gun comprising:
a cathode comprising an emission surface that is curved about a central axis and is configured to emit electrons; and
an accelerator operable to accelerate the electrons in a radial direction toward a target region on the central axis, wherein the emission surface has a width in an azimuthal direction, and the emission surface has a height oriented perpendicularly to the width, and wherein the width is at least ten times the magnitude of the height; and
a target structure arranged in the target region.
15. The radiation generating apparatus of claim 14 , wherein the target structure is configured as an x-ray target.
16. The radiation generating apparatus of claim 15 , wherein the accelerator is configured to accelerate the electrons to an energy of at least 25 keV.
17. The radiation generating apparatus of claim 16 , wherein the accelerator is configured to accelerate the electrons to an energy of at least 100 keV.