Shape of the Modified Compton Line for Hydrogen and Ceylon Graphite Scatterers

Abstract

Hydrogen under ten atmospheres pressure was used to scatter almost directly backward the characteristic $K$ radiation of a molybdenum-target x-ray tube. After an exposure of 1914 hours in a focusing curved-quartz-crystal spectrograph the resulting modified line was studied with a microphotometer. The breadth of the composite modified line of the alpha-doublet was 15.2 x.u. This is ten percent greater than the breadth computed by B. Hicks from the electron momentum distribution. That the discrepancy is greater for ${\mathrm{H}}_2$ than for the previously studied He is probably because the ${\mathrm{H}}_2$ calculations were not carried to so high a degree of approximation. The unmodified line was completely absent. The shift as determined by fluorescence reference lines is less than that required for free electrons by an amount appropriate to the binding energy of electrons in the ${\mathrm{H}}_2$ molecule.