The X-Ray Shadow Microscope

Abstract

Shadow projection permits higher resolution and simpler operation than other methods of x‐ray microscopy. A point source, less than 1μ in diameter, is obtained by the use of magnetic electron lenses and used for projecting shadow images at a primary magnification up to 100× with an exposure time in the order of minutes. The use of a metal foil as target and tube window insures high intensity at the specimen, which is in air. A resolving power little short of the best optical performance has been obtained with an accelerating voltage of 10 kv. The practical limitations to resolution, contrast, and exposure time are discussed in detail. A resolution of 100A should be practicable, but only with longer x‐rays and an exposure of the order of 1 hour.