Application of ion beam to element and density analysis

The light ion beams from a compact AVF cyclotron at IMS have been utilized to element and density analysis of biomedical samples. A beam line was constructed which is capable to focus the 27 MeV α and proton beams to a spot as small as 15 μm in diameter. A doublet of quadrupole magnets was used as a focussing lens. The demagnification factors were -3.3 and -15.7 in CD and DC planes, respectively. The 27 MeV α microbeam has been utilized for PIXE analysis of biomedical samples. The experimental results of the application of the technique to the study of cataract are presented. Intending to investigate the possible role of ions in the lens opacification process, the changes in the distributions of minor elements in lens, such as S, Cl, K and Ca, were studied for an experimental cataract of mouse. The 25 MeV proton microbeam has been utilized to measure the density distributions in biomedical samples based on the computed tomography principle (proton-CT), where the energy loss of the incident particles after penetrated through the sample was measured by a SSD. The CT image with a spacial resolution of 60 μm and density resolution better than 0.1 % were obtained for small soft tissue samples. (author)