L-Shell Ionization by Protons of 1.5- to 4.25-Mev Energy

Characteristic $L$-shell x-rays produced when protons of 1.5- to 4.25-Mev energy are stopped in Ta, Au, Pb, and U have been studied with a NaI scintillator. The absolute cross sections for x-ray production are presented. By correcting these values for Auger transitions, the $L$-shell ionization cross sections have been determined. At 3 Mev, the x-ray production cross sections are 104, 74, 54, and 24 barns for Ta, Au, Pb, and U, respectively.