Cross section for induced x-ray emission in some elements by 950-keV protons

The cross section for x-ray characteristic fluorescence excited by 950-keV protons has been measured for 12 elements: Cl, K, V, Cr, Fe, Ni, and Cu for $K$-shell emission and Rb, Y, Ag, Sm, and Gd for $L$-shell emission. The results for Cl, K, V, Rb, and Y are new data. We obtain ${\sigma }_K^{\mathrm{X}}=260\mathrm{}\pm 15\%$ for Cl, ${\sigma }_K^{\mathrm{X}}=121\mathrm{}\pm 15\%$ for $K$, ${\sigma }_K^{\mathrm{X}}=22.7\mathrm{}\pm 10\%$ for $V$, ${\sigma }_L^{\mathrm{X}}=405\mathrm{}\pm 15\%$ for Rb, and ${\sigma }_L^{\mathrm{X}}=350\mathrm{}\pm 15\%$ for Y, all cross sections (in barns) having been measured at 950-keV proton energy. Moreover, we deduce for Y a new value of ${\overline{\omega }}_L=0.14\mathrm{}\pm 15\%$. The results for the remaining elements are compared with the results of similar measurements. The experimental values are also compared with the predictions of the binary-encounter approximation and of the binding-energy-corrected plane-wave Born approximation. Both theories predict higher $K$-shell ionization cross sections than observed.