CONICET | Buscador de Institutos y Recursos Humanos

The firsts imaging technique using a x-ray based on the differences in absorption of the sample (conventional absorption radiography). Several improvements were made in detectors and x-ray sources in order to enhance imaging quality. A new x-ray radiographic imaging, called diffraction-enhanced imaging (DEI), based not only on attenuation but also the refraction and diffraction properties of the sample. This method shows additional information that is not available with standard radiography. DEI is nowadays an important topic of research and has been applied to many types of objets, for example, biological samples. After the good result of the first experiments on DEI at LNLS[1], a new experimental set-up was tested to increases the imaging quality of biological and industrial samples. The XRD2 beamline was used with the beamline mirror in defocusing setup in order to obtain an almost parallel beam on the vertical direction. The horizontal divergence (0.7 mrad) and the photon energy (10 keV) were defined using the beamline sagitally monochromator. To improve the quality of the beam, (decreasing the vertical divergence to 60μrad on the sample), a two Si(333) channel-cut was mounted on the double axis diffractometer in a non-dispersive geometry.With different angular position of the Bragganalyzer crystal (second channel-cut) around the maximum of the rocking curve, it was possible to obtain bright and dark field images to enhance details of the sample. For imaging samples with 2020mm2 the sample and the detector (direct-conversion CCD camera of 12421152 pixels, each 22.522.5μm2) was mounted in an automatic system of two vertical translators. Images of biological samples like preliminary patterns, bat fetus[2] and human tissue were obtainedand compared with conventional absorption radiographs. Also was mounted in the sample support a tomographic table in order to obtain diffraction enhanced tomographic images.

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