X-ray tube with flexible intensity adjustment

An x-ray tube, comprising:

• a thermionic cathode having a flat electron emission surface;
• a plurality of electrostatic electrodes;
• and
• a target;
• wherein the x-ray tube is designed for generating an electron beam propagating from the cathode to the target along a beam axis running along a z direction and for generating a microfocus spot on the target;
• wherein the target is configured as a target anode;
• and wherein the x-ray tube comprises:
• a control electrode, located in z direction in front of the flat electron emission surface, and configured as an aperture with a first aperture opening smaller than the emission surface, the first aperture opening having a contour which is rotationally symmetric with respect to the beam axis;
• a focusing electrode, located in z direction in front of the control electrode, and configured as an aperture with a second aperture opening larger than the first aperture opening, the second aperture opening having a contour which is rotationally symmetric with respect to the beam axis;
• a beam shaping electrode, located in z direction in front of the focusing electrode and before the target anode, and configured as an aperture with a third aperture opening, the third aperture opening having a contour which is aligned with an xy plane and non-rotationally symmetric with respect to the beam axis;
• wherein the thermionic cathode and the beam shaping electrode are electrically connected;
• with x, y, z forming a Cartesian coordinate system.