A study on proton induced X-ray analysis and its application to environmental samples

Proton induced X-ray analysis has been studied by the 5 MV Van de Graaff of Tohoku University emphasizing on backing materials and angular dependence of background. The method has further been applied to analyses of some environmental samples. From experimental results, it was found that 4 μm Mylar foil among Formvar, Mylar and carbon gives sufficiently low background spectrum, high sensitivity and good mechanical strength. The detection limit is much improved at the backward direction with respect to the incident beam comparing with that at 90° which has usually been adopted. The analytical results on soil and aerosol samples were compared with those by the Atomic Absorption Spectrophotometrical method (AAS). Vanadium can easily be analysed by this method, but not by the AAS method. Milk and human milk were also analysed.