Characterization of materials using computerized tomography by X-ray transmission

• Grant number: 05/04727-6
• Support type: Regular Research Grants
• Duration: September 01, 2006 - August 31, 2008
• Field of knowledge: Physical Sciences and Mathematics - Physics - Nuclear Physics
• Principal Investigator: José Martins de Oliveira Junior
• Grantee: José Martins de Oliveira Junior
• Home Institution: Pró-Reitoria de Pós-Graduação e Pesquisa. Universidade de Sorocaba (UNISO). Sorocaba , SP, Brazil

Abstract

Internal visualization of materials became possible with Computed Tomography (CT), without the need to physically open the object. This technique was originally developed for the analysis and diagnosis of the human body, and only recently has broadly been used in non-destructive evaluation of materials. CT is a technique based on the acquisition of object cross-sections, through the analysis of the radiation intensity transmitted in different directions. The outstanding contribution of tomographic image is the possibility to distinguish regions with different attenuation coefficients or densities of superimposed structures, that otherwise, wouldn't be visible with conventional radiography. The CT is a powerful tool for utilized in non-destructive physical analysis. CT can be used to identify the material mean atomic number and its density or attenuation coefficient. It can be applied in different areas of knowledge, since details inspections in lives organism; such as electric electronics components control production by industry, soil composition analysis, inspections in civil construction industry, drug quality control, among others. Recently a mini computerized tomograph was projected, constructed and tested by us and it was installed in the "Laboratório de Física Nuclear Aplicada da Uniso (LAFINAU)" and denominate "Mini Tomógrafo Computadorizado da Uniso (MTCU)". It operates with a gamma ray source of 241Am (100 mCi of intensity) and use one NaI(Tl) solid state detector. This system features translation and rotation scanning modes, a 100 mm effectively of view, and 1 mm spatial resolution and between 7 % to 10 % of density resolution. This system is thus a first generation CT scanner that use parallel beam and translate-rotate geometry. The images generated by MTCU have low spatial and density resolution and the time of acquisition of one image is too much. This project propounds transform the MTCU, that is a first generation tomography, in a third generation CT scanner that operate with rotate-only scanning geometry and use a fan beam X-ray and a detector array. To implement this proposal, we're requesting to FAPESP a X-Ray source, detectors array and appropriated electronics to control these equipments. As several groups from UNISO are involved in this project as well as external institutions, the LAFINAU is becoming a multi-user and interdisciplinary laboratory. (AU)