Energy dependence of the X-ray production cross section of Cu and Ag for 150 to 800 keV proton and He+ bombardment

Relative K-shell x-ray production cross sections have been measured for thin targets of Cu and Ag for proton and He+ impact in the energy range 150 to 800 keV. The experimental values are compared to the nonrelativistic plane wave Born approximation (PWBA), the PWBA with corrections for Coulomb deflection and binding effects (PWBABC), and the binary-encounter approximation (BEA). The PWBABC theory provides the best agreement with relative experimental cross sections. For protons, the agreement is within 2% for values of the scaled energy variable y=eta/(epsilon theta)2 > 0.011; for y < 0.009, however, the deviation reaches about 10%. For helium a 10% deviation appears at y approximately 0.007. An explanation for these deviations is given.