| 摘要 |
PURPOSE:To make it possible to always retain voltage of a photographing tube within the most suitable range by changing an allowable load rate of an X-ray tube according to the thickness of a subject. CONSTITUTION:When starting cinematographing in an X-ray control device 81 according to the conditions such as a cinematographing condition KV, mA, a frame number per sec, a cine-one cut time and pulse width of one frame, a photoelectric tube 5 detects a quantity of light to control actual pulse width with a phototimer device 6 so as to always retain cinefilm density constant corresponding to the conditions. The pulse width (actual pulse width) controlled by the phototimer device 6 is sent to a pulse width comparator 83 to be compared with the set value of a pulse width setter 82. A proportional signal of a difference between the actual pulse width output from the comparator 83 and the set pulse width is sent to an X-ray controller 81 to change KV of the cineconditions in the next frame. Thereby, when KV is deflected from a suitable range, this X-ray load rate is made to be changed. |
