Quantitative surface analysis using ion-induced secondary ion and photon emission

The secondary ion and photon yield from a stainless steel target bombarded with Ar+ ions has been studied. The yields have been measured in a variety of oxygen background pressures. From the distribution of photon intensities, an effective arc temperature, T, for the bombarded surface has been derived. An empirical relationship has then been used to obtain the free electron density Nsub(e), of the ion bombardment induced surface 'plasma'. The derived values of (T,Nsub(e)) are then used in the Andersen-Hinthorne model, to calculate the changes in the Cr/Fe ratio as a function of the oxygen background pressure. The Cr/Fe ratio under the cleanest conditions available agrees very well with an electron microprobe measurement of the same ratio, while the changes in the Cr/Fe ratio as a function of oxygen pressure are consistent with electron spectroscopy studies of the changes in the Cr/Fe ratios in oxidised stainless steel. (Auth.)