Computer microtomography using a laboratory x-ray fluorescence microbeam spectrometer - A feasibility study

Absorption tomography imaging of small objects was performed using parallel beam geometry and a laboratory microbeam x-ray fluorescence (g-XRF) spectr ometer. Two x-ray tubes, with Mo and Cr anodes, were used to perform tomogr aphic imaging with different energies, namely 5.411 and 17.5 keV. The prima ry beam was collimated-focused using a tapered single glass capillary with an exit diameter of about 12 mum. The spatial resolution of the collimated x-ray beam was about 25 mum (FWHM). The attenuated primary beam was measure d using a standard Si(Li) energy-dispersive detector. Depending on the beam intensity, two measuring modes were utilized: direct measurement of the tr ansmitted beam and measurement of the secondary radiation excited by the tr ansmitted beam in the yttrium target. The tomographic images of several sma ll objects were obtained, namely a glass capillary, the tip of a match, a b urned wooden stick and the head of a fly. The limitations of computer micro tomography imaging using laboratory mu -XRF are discussed and the solutions to the approached problems are presented. Copyright (C) 2001 John Wiley & Sons, Ltd.