Production of Characteristic X-Rays by Protons of 1.7- to 3-Mev Energy

Characteristic x-rays produced when protons of 1.7- to 3-Mev energy are stopped in thick targets of Mo, Ag, Ta, Au, and Pb have been studied using a NaI scintillator. $K$ and $L$ radiation for the three heavy elements produced well-separated differential pulse-height peaks, while only the $K$ radiation was detectable for Mo and Ag. Cross sections for $K$ ionization have been calculated, with corrections for the Auger effect, and compared with the theory. Ratios of experimental to theoretical cross sections vary from one to four, with good agreement for the light elements and low proton energies. The measured cross sections at 2.4-Mev proton energy are 11, 3.0, 0.036, 0.016, and 0.010 barns for Mo, Ag, Ta, Au, and Pb, respectively.