Characteristic X-Ray Production in Single Crystals (Al, Cu, W) by Proton Bombardment. II. Protons of 250 to 1560 keV

The study of the effect of proton channeling on the production of characteristic x rays in thick, metallic single crystals has been extended by the use of protons with energy between 250 and 1560 keV. The x-ray yields of Al $K$, Cu $K$, Cu $L$, W $K$, W $L$, and W $M$ were measured as a function of the relative orientation of the crystal with respect to the direction of the incident beam. As in the previous study (Part I) minimum values of the x-ray yield were observed when the beam direction lies in crystal planes or along crystal directions having low indices. The relative x-ray yield is presented as a function of the orientation of the crystal planes with respect to the direction of the incident beam. The data indicate that the widths of the resulting curves (yield versus orientation in a plane) depend on the proton energy $E_P$ as 1 ${\left({\mathrm{E}}_P\right)}^{\frac{1}{2}}$. However, for a given element, the widths do not depend on the particular shell ionized.