可変焦点X線管及び応用に就いて

抄録

We have tried to enlarge or cantract the focus by applying positive or negative voltage to a grid of an ordinary X-ray tube (which has no srecial structure and is on sale to the public) and applied this method to an usual radiography. This method, by applyins high negative voltage, also can be used as a vacuum tube switch. The following are the actual results we have heretofore collected on the above-mentioned.