1957 Volume 13 Issue 2 Pages 122-130
Using the double focus-tube (# 5065) for the enlargement-radiography under BIAS voltage, we performed the radiography, observed how small the effective focus could be become, and investigated the size and shape of the focus, and the centering condition of electron under BIAS voltage. And them the size of the effective focus could be measured from the enlarged image applying the following formula.[numerical formula]Thus we were successful in the twice enlargement-radiography of the chest.