Design and verification of measurement system for ion dose normalization in microbeam scanning PIXE system at NIRS

Microbeam scanning PIXE (micro-PIXE) analysis is a significant tool for obtaining information of multi-elemental distribution in the samples, as a two-dimensional image on the surface of the samples, such as mammalian cells, tissues, and other environmental monitoring species, Recently, in addition to elemental distribution information, quantitative analysis for the elements are desired. To make quantitative measurement possible, real-time beam monitoring system that gives precise measurement of exposure dose, and outputs independent from the targeted sample, and enables to keep the beam resolution of micrometer size. In this paper, we report about the design and development of ion dose normalization system for beam current monitoring. The beam current was monitored by detecting secondary electrons induced from a 10 g/cm2 thick carbon foil by ceramic channel electron multiplier (CEM). This carbon foil was attached to a sample holder, which was set on the sample targeted position. The output value of the CEM was proportional to the Faraday cup installed just after the sample position. Beam resolutions was measured using off-axis STIM by scanning at copper grid and were estimated at 1.79 and 1.72 m for the horizontal and vertical directions, respectively, sufficient for routine micro-PIXE) analysis.11th International Conference on Nuclear Microprobe Technology and Applications 200