X-ray tubes

These tubes serve as the source of X-rays in medical instruments. They are a vacuum tube with two electrodes, on which a source of very high voltage (tens of kV) is connected. Electrons fly out of one heated electrode, are accelerated by the high voltage and collide with the other electrode. A part of their energy is converted to X-ray radiation. The electrode heats up with the impacting electrons, so more powerful tubes would use a rotating electrode powered by an alternating magnetic field coming through the glass wall. The anode would rotate, so the point of electron impact on the surface would continuously change.