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- Author or Editor: H. Imaseki x
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Abstract
In 2000, micro-beam scanning particle induced X-ray emission (PIXE) analysis system was installed in NIRS. This system provides the ability of multi-elemental mapping on maximum 2.5 mm×2.5 mm area in a spatial resolution of about 1 μm with quadrupole triplet magnets and a scanning coil. The estimated beam size on good tuning was 0.40×0.65 μm2, that is one of the best capacity of micro-beam scanning PIXE system in the world. The performance was tested using small biological samples such as fish scale, pollen and small fish eye. Fine elemental maps were obtained in the samples of about 30 μm to a few mm size in the special resolution of about 1 μm.
Abstract
The resolution of a 33±3 
m microprobe focussed with quadrupole doublet installed at the 3 MV Van de Graaff of the National Institute of Radiological Sciences was used for this analysis. Brown algae, Hijiki,Hizikia fusiforme was the sample target bombarded with a 2 MeV proton beam collimated mechanically into a rectangular image of 100 m × 700 m. Scanning across the sample target prepared into a longitudinal section from the caulis of the algae provided the following observations. More than 12 elements such as Al, Si, P, Cl, Ca, Mn, Fe, Cu, Zn, As, Br and Sr were determined simultaneously, together with their distributional information across the diameter. In the medullary layer, Mn and Zn were specific in their accumulation, while the deposition of Fe, Cu, As and Br were observed to be high in the epithelial layer, especially Fe and Cu which were found on the surface, where they contact ambient sea water, but no significant change in pattern was indicated for such elements as Al, P and Cl. The PIXE microprobe analysis was, therefore, effective in its detectability for elements below a few ppm level, resultantly provides further possibilities for collecting information from bio-medical and environmental samples on trace characterization of elements.
Abstract
The balance of essential elements in organisms can be changed by environmental stresses. A small fresh water fish, the medaka, was irradiated with X-rays (total dose: 17 Gy, which is not a lethal dose for this fish). Essential elements in the liver, gall bladder, kidney, spleen, heart and brain of the fish were measured by the particle induced X-ray emission (PIXE) method and compared with those of a control fish. Various changes in the elemental balance shift were observed. The PIXE method can analyze many elements in a small sample simultaneously, and so the changes in elemental content induced by irradiation were readily determined.
Abstract
Microbeam analysis is used in biomedical and environmental sciences to determine the presence and concentration of trace elements. However, quantitative analyses of biological samples are challenging because the chemical and physical compositions of existing standards differ from those typically encountered in biological samples. We developed a thin standard using polyvinyl alcohol and assessed its quality by microbeam scanning particle induced X-ray emission (micro-PIXE) analysis. The relationship between metal concentration and X-ray intensity was linear for certain standards up to 500 μg·g−1. Using this new thin standard, micro-PIXE analysis of Zn content in samples of human hair agreed well with analysis performed by inductively-coupled plasma mass spectrometry, validating the use of these new thin standards for quantitative mapping with microbeam analysis.
