Concave Spherical Crystals of Barium-Copper-Stearate for Use in Long Wave-Length X-Ray Spectrometers

Abstract

To perform the double function of diffracting and focusing a monochromatic beam of x‐rays, multiple monomolecular layers of barium‐copper‐stearate were deposited upon an accurately ground concave spherical surface of glass. With a spherical crystal of radius of 218 cm, grating space of about 50.5A, preliminary photographs of the Al Kα,β region, component lines not resolved, were obtained in 30 minutes at 3 kv and 15 ma. It is believed that the intensity and resolving power from such a spherical grating are adequate for measurements with an ionization chamber of absorption coefficients at wave‐lengths above 8A.