| 摘要 |
PURPOSE:To produce stable pulse X-rays and greatly improve the rate of dose reduction by storing the heating voltage at the end of the preceding exposure as a predetermined voltage level and applying a voltage of the predetermined level to a filament as soon as exposure is completed to preliminary heat the filament. CONSTITUTION:The heating voltage at the end of X-ray exposure is maintained over the period of nonexposure by using a heating voltage detection resistance 6 to detect heating voltage during X-ray exposure and by charging a capacitor 10 through a relay contact 12. After X-ray exposure is completed, a relay 9a is switched to close the circuit and even during the period of nonexposure filament-heating voltage is maintained at the same level as the voltage of the capacitor 10 at the end of X-ray exposure. Due to the above structure, there is no possibility that the heating level increases to the maximum during the period of nonexposure. Therefore, stable X-rays can be produced and the rate of dose reduction can be greatly improved. |
