NETWORKS FOR LIMITING X-RADIATION FROM CATHODE RAY TUBES

摘要

Operation of a cathode ray tube above the Isodose line is prevented by generating voltages that are proportional to both the EHT supplied to the cathode ray tube and the beam current of the cathode ray tube. These voltages are applied to a sensing device, such as a neon tube, which generates a trigger pulse when the voltage across it exceeds some predetermined magnitude. The sensing device is selected so that the trigger pulse is generated always below the Isodose line. The trigger pulse is used to inhibit operation of the cathode ray tube as by interrupting the supply of EHT to the cathode ray tube.