"Radiographic Technique for Densitometric Studies Using Heavy Ion Microbeams"
Different analytical techniques are typically used to perform multi-elemental and densitometric analysis by means of particle beams with micrometric space resolution. Usually, those analyses are respectively performed by PIXE and STIM. Traditionally, to characterize the trace element concentrations in a specimen two different experiments are required with differences in setups and types of detectors employed, as well as in the necessary ion current intensities. In this work, we discuss the latest results in the development of a new technique that synthesizes both analyses in just a single one, by means of heavy ion induced X-ray emission. This technique, implemented for the first time at the Tandar Laboratory, employs a second target in addition to the sample under study. The multi-elemental information of the specimen is provided by its PIXE signal and its densitometric information is supplied by the PIXE signal of the secondary target, which is placed immediately behind the sample under analysis. These PIXE signals are produced and acquired during the same experiment, allowing the analysis of both features (composition and density) at the same time. The X-rays originated in the secondary target are attenuated when traversing the specimen in the direction of the detector and consequently a radiographic image of the specimen is obtained. In this case, the characteristic X-rays of the secondary target act like a monochromatic secondary source. In the present work, a method to estimate the thickness of specimens is introduced and compared with estimations performed by the STIM method.