Development of a multi-energy CT for small animals: Characterization of the quasi-monochromatic X-ray source

A new multi-energy CT for small animals is operative (now only in scanner mode) at the Physics Department of the University of Bologna. The system makes use of a set of quasi-monochromatic X-ray beams produced by means of an highly-oriented pyrolytic graphite Bragg monochromator. This source is able to provide beams with energy tunable in a range from 20 to 70 keV. Here we present a complete characterization of the source. A theoretical model of the source has been analyzed, according to a very-well known theory for diffracting crystals. The beams have also been characterized in resolution and intensity, all over the accessible range, and we present here some measured spectra.