PURPOSE: To prevent a metallic X-ray tube from breakage, by always keeping the anode potential higher than the potential of a metallic part.
CONSTITUTION: From a control unit 4 for the radiation time, pulselike voltages of a reference width are output, whereby pulse units 2 and 3 are controlled. A high voltage switching-elements SW1 and SW2 are respectively actuated by the pulselike voltages from the pulse units 2 and 3 and X-rays are radiated by a metallic X-ray tube 1. Even if the switching-element SW2 on the negative side is brought into an "off" state, the switching-element SW1 on the positive side still retains its "on" state and the anode potential is always kept higher than that of the metallic side. Therefore, electrons generated from a cathode K of the X-ray tube 1 do not flow into a metallic part M but flow in their entirety into an anode A.
YAMAMOTO HIROSHI
SUZUKI TOORU
