M-SHELL X-RAY-PRODUCTION IN HEAVY-ELEMENTS BY LOW-ENERGY PROTONS

Measurements of M-shell X-ray production cross sections in selected heavy elements (73 ≤ Z2 ≤ 90) have been performed for proton impact of energy 0.1-0.6 MeV. X-rays were collected by a Si(Li) detector, carefully calibrated for low-energy efficiency, and they were normalized to the projectiles that were elastically scattered into the surface barrier detector. The measured M-X-ray production cross sections are compared with the predictions of the first Born approximation, the semiclassical approximation, and the ECPSSR theory which corrects for energy loss, Coulomb deflection, binding-polarization and relativistic effects. The comparison of the present data with our earlier measurements and the data reported by other authors is discussed in detail. Strong underestimation (up to a factor of about 5) of experimental data by the ECPSSR theory is observed for the lowest energies. © 1990.