The production of characteristic X-rays by proton bombardment, and the ratio of characteristic to continuous radiation

Abstract

Absolute measurements of K and L characteristic X-rays produced in thick targets of Ni, Cu, Mo, Ag, and W are reported. The data for K X-rays are compared with a theoretical result obtained by integration of the expression for the cross section given by Merzbacher and Lewis (1958). The expression for yield as a function of energy can be put into a very simple form without the need for an empirical function, and this is verified experimentally. A new absolute comparison can be made between thick-target theory and the present data for nickel and gives good agreement. Tungsten L-radiation is investigated, and spectra are obtained using a Si(Li) detector. The number of L-ionizations per proton in tungsten is found to be greater than the number of K-ionizations expected in an element with a K-shell binding energy equal to the LIII binding energy of tungsten, by a factor of 2.9. The proton bremsstrahlung is measured and the ratio of characteristic to continuous radiation found to be 1.63*103 for 420 kV protons on nickel. This is shown to be about 3 orders of magnitude greater than for electron bombardment under optimum conditions.