Experiments with Fluorescent X Rays in the 10- to 50-Å Wavelength Region

Apparatus for the production, dispersion, and detection of soft fluorescent x-rays (10 to 50 Å) is described. The apparatus includes a new type of gaseous discharge x-ray tube capable of operating at 3000 v and 200 ma, a servo-type vacuum controller for maintaining constant x-ray tube current, and built-up films of heavy-metal soaps for use as analyzing crystals. Photographs are included of fluorescent spectral lines of carbon from graphite (Kα, λ=44.5 Å) and of copper (Lα, λ=13.3 Å) obtained, respectively, in 2 and in 4½ hr.