| 摘要 |
PURPOSE:To surely prevent an X-ray tube from being overloaded, by directly detecting the temperature of a target of the X-ray tube and ceasing the irradiation of an X-ray when the target reaches a critical temperature. CONSTITUTION:When a pulsed tube voltage is applied to an X-ray tube to perform the irradiation of an X-ray and start a photographing work, the temperature of a target is gradually increased and followed by a gradual increase of outputs of an amplifier 10 and peak value detecting circuit 13. When the output of the amplifier 10 exceeds a rated value, the output of an arithmetic comparator 12 is inverted to a state of low level causing the X-ray to be automatically stopped its irradiation. When a photographing work is finished, a virtual cooling curve is output from a false signal generator circuit 14, according to which the target temperature is calculated, and on the basis of said temperature a photographing condition can be discriminated if it exceeds the rated value of the X-ray tube. |
