抄録
This paper is concerned with our very fine focus of a fixed anode tube applied to the enlargement radiography. The focal spot of 0.126mm. in size, acertained under the geometrical and experimental consideration, was made by electron beams narrowed after the principle of bias phenomena. By means of this very fine focus method any part of the body can be taken in sharp enlargement radiogram. Roentgenographic conditions are de-tailed. Up to now, 930 times exposures were made with this bias tube with no ruin on the surface of the target.
