| 摘要 |
PURPOSE:To prevent the occurrence of overshoot by giving a time constant to rise- up characteristics at the emission starting time of control signal to supply to a current control element by which current to supply to X-ray tube is controlled and the emission control of X-ray tube is made. CONSTITUTION:A signal according to the tube voltage and the tube current is outputted from the tube voltage and tube current input units 9 and 10 and then synthesized at the signal synthesizing circuit 11. The output of the circuit 11 is compared with reference value and judged at the comparison and decision circuit 12, according to the compared value, optimum rise-up time constant of grid voltage is selected, and the time constant signal output of the time constant signal-generating circuit 13 according to the selectively set time constant is applied to the amplifier 14 synchronously with the emission signal of X-rays. The output of the amplifier 14 is given to the grid control circuit 15 by which tetrode valve is brought into switching operation controllably and therefore anode voltage according to the rise- up of the grid voltage is outputted. |
