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  • Author or Editor: D. Grozdov x
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Abstract  

It has been demonstrated that pixel-by pixel processing of series of autoradiography images for revealing the dynamics of decay of the induced radionuclides is an efficient approach for mapping of radionuclides in the sample in activation autoradiography. Concepts of virtual scanner and corresponding software for linearization of dependence of optical density on scanner response (luminosity) have been introduced. The concept provides unification of the subsequent processing of autoradiograms, irrespective of the method as to how the digital image has been obtained. Algorithms and the software for estimation of decay parameters of a radionuclide mixture for each pixel using a series of coaxially positioned images have been developed. The software is able generate a set of the derivative meta-images allowing a conclusion to be made about the presence of the inclusions in question. To increase the reliability of radionuclide mapping it is suggested to use analysis of distribution of half-life values estimated for pixels of image zone(s) pointed by a special mask.

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Abstract  

The activating field of microtron bremsstrahlung is characterized by sharp recession of intensity in lateral and longitudinal directions. Therefore, the irradiation of several samples simultaneously results in their different activation which is a source of systematic error. Evaluation of correction coefficients needed for quantitative analysis by measurement of thin copper disks placed between the samples does not result in acceptable data. For these purposes a method for 3D-activating field monitoring and Monte-Carlo simulation for computation of the needed correction coefficients has been developed. The monitor represents the copper foil wrapped round the sample assembly. The autoradiogram of the irradiated monitor is used for characterization of the activating field. The Monte-Carlo simulation model involves both the field characteristics and the results obtained while making single training analysis.

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Abstract  

It has been demonstrated that digital gamma-activation autoradiography is an effective method for detection of platinum-palladium micro inclusions in the copper-nickel polymetallic ores of complex composition. Just two measurements of the samples (after irradiation and a week of cooling) are enough for contrast detection of such inclusions. To extend the method capabilities, a procedure of treatment of a set of the images obtained while cooling the samples has been developed. The procedure permits control of the inclusions composition and estimation of the main components ratio. It has been stated that gamma-activation autoradiography is highly suitable method for screening detection of inclusions in geological samples and it is quite reasonable to combine with scanning electron microscopy or X-ray microprobe techniques for further detailed investigations of the found inclusions peculiarities.

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