OPTIMISATION OF THE X-RAY FLUORESCENCE IMAGING SYSTEM FOR MAPPING OF PIGMENTS IN HISTORICAL PAINTINGS

The basic principle of operation of the X-ray fluorescence imaging system of cultural heritage painting has already been proven and presented elsewhere. In this paper, we report on optimisation of the pilot imaging system based on Gas Electron Multiplier (GEM) detector, a pinhole camera and a dedicated data acquisition system (DAQ). We focus on evaluation of detection capability of the system for various combinations of the pigments layouts. Carefully designed and prepared painting phantom with stripes, which overlay each other, has been investigated. The selected pigments and their composition were chosen in such a way that the energy resolution of the system was critical capability of reviling hidden layers. Even though the investigated pigments are based on elements which differ in Z by one, the system is capable to distinguish them well.