Development of a low-energy PIXE analysis system based on an ion implanter

A low-energy particle-induced X-ray emission (LE-PIXE) analysis system with precise energy control was developed based on a 200 kV ion implanter. The energy dependence of LE-PIXE was evaluated using a millimeter-sized low-energy proton beam by varying the incident energy with precision better than 5 keV. LE-PIXE spectra were obtained for protons with an energy range of 40–120 keV. The LE-PIXE sensitivity was approximately proportional to the sixth power of the incident proton energy. The characteristic X-ray intensity strongly depended on the depth distribution of elements in the target. Experimental evaluation with multilayered thin film samples demonstrated that LE-PIXE was effective for depth distribution analysis to 1000 nm deep. Multilayered structures containing four different elements were characterized by LE-PIXE analysis using multiple probe energies.