Application of RBS and PIXE to measure stopping power and chemical composition of bone samples and interface diffusion in multilayer polymeric films

L.M. RODRÍGUEZ; L. PROVENZANO; S.J. GONZÁLEZ; L. SALAZAR ALARCÓN; E.D. MARTÍNEZ; G. BERNARDI; D. FREGENAL

Trieste

Workshop; Joint ICTP-IAEA Advanced Workshop of High Sensitivity 2D and 3D Characterisation and Imaging with Ion Beams; 2016

ICTP - IAEA

In this work we present two different applications of the 1.7 MV Tandem accelerator facility placed in Bariloche, Argentina.Boron Neutron Capture Therapy (BNCT) is a cancer treatment that was designed to selectively deliver heavy charged particle radiation to tumors at the cellular level. This technique use the 10B(n,a)7Li reaction and the selective boron uptake by tumor cells. After boron disintegration the a particle have a range in tissue comparable with cellular dimensions (~12-14 mm). In order to assess a proper dosimetry, it is necessary to know the boron concentration of the tissues irradiated by neutrons. The charged particle spectrometry developed in the University of Pavia [1] allows determining boron concentrations down to 1 ppm in thin soft tissue sections. Extending this technique to analyze hard tissues of interest in osteosarcoma disease requires the knowledge of the stopping power of a particles in bones. We will show here results of the stopping power of a particles measured using the energy shift of a heavy metal thin film RBS spectrum interposing decalcified slices of bones in front of the detector. These data and the knowledge of chemical composition with maximum detail using PIXE technique are used to improve simulations in order to extend stopping power values to samples with calcium [2].In other area of work we study polymeric multilayers used in microfabrication. During SU-8 standard photolithography process a patterned topography is formed with a characteristic height profile produced by the different shrinkage of the UV exposed and masked regions. There is a change of wettability, film solubility and topographic modifications on SU-8 films of different thicknesses and show its relevance in the formation of spinning-flow arrays on top layers made from positive photoresists [3].We will show here results of the application on these systems of RBS thechnique to measure the elemental composition profile and to understand interface diffusion processes of the photoresists multilayer and its dependence with fabrication variables like baking, UV exposure and development [4].