PIXE-INDUCED XRF WITH TRANSMISSION GEOMETRY

PIXE-induced XRF, or PIXE-XRF, is an analytical method using nearly mo noenergetic X-rays from the particle bombardment of a primary target t o induce X-ray fluorescence. This method gains two main advantages ove r the conventional PIXE method. First, with the proper selection of th e primary target, the spectral interferences from major elements in th e sample can be eliminated. Second, sample damage is greatly reduced, so that it is more suitable for the analysis of heat-sensitive, volati le and delicate specimens. In the present paper, a transmission geomet ry of the primary target for PIXE-XRF is proposed. The primary X-ray y ields were calculated as the functions of primary target thickness for proton and helium particles at various energies. The selection of exp erimental conditions, including the primary target thickness, the ion beam and its energy, is discussed. The preliminary experimental result s showed that with the transmission geometry the characteristic X-ray yields of the specimen were two orders of magnitude higher than those obtained with the reflection geometry arrangement, enabling the detect ion limits for both the thin and the thick target to reach sub-ppm lev el. Some preliminary applications are presented.