| 摘要 |
PURPOSE:To reduce the loss caused by tetrodes by maintaining the voltage of an X-ray tube constant by detecting voltage applied across the electrodes of the X-ray tube by means of high-voltage bleeders, and regulating the tetrode connected to the anodic-bus side according to the detected voltage. CONSTITUTION:Tetrodes 23 and 24 are connected to the positive side and the negative side of a rectifier 22, which rectifies a three-phase high-voltage power source, so as to actuate an X-ray tube 25. The positive-side and the negative- side voltages of the tube 25 are detected with bleeders 30 and 31, are compared with a set tube-voltage signal 29, and control the grid biases of the tetrodes 23 and 24 after passing through photo-electron converting circuits 40 and 41. At the same time, voltage applied across the electrodes of the tube 25 is detected with a bleeder 28, and fed back to a controlling circuit 26 of the tetrode 23 on the positive side so as to control the tetrode 23. As a result, voltage applied across the electrodes of the tube 25 can be maintained constant. Besides, the loss caused by the tetrodes 23 and 24 can be reduced by burdening the tetrode 23 with the absorption of the pulsation. |
