The Spectrum of Scattered X-Rays

Abstract

The spectrum of molybdenum $\mathrm{K}\alpha$ rays scattered by graphite at 45°, 90° and 135° has been compared with the spectrum of the primary beam. A primary spectrum line when scattered is broken up into two lines, an "unmodified" line whose wave-length remains unchanged, and a "modified" line whose wave-length is greater than that of the primary spectrum line. Within a probable error of about 0.001 A, the difference in the wave-lengths ($\lambda -{\lambda }_0$) increases with the angle $\theta$ between the primary and the scattered rays according to the quantum relation $(\lambda -{\lambda }_0)=\lambda (1-cos\theta )$, where $\lambda =\frac{h}{\mathrm{mc}}=0.0242\mathrm{}$ A. This wave-length change is confirmed also by absorption measurements. The modified ray does not seem to be as homogeneous as the unmodified ray; it is less intense at small angles and more intense at large angles than is the unmodified ray.