Nondestructive Investigation on Elemental Distributions of Oil Painting Using 3D Micro-XRF Spectroscopy

Confocal 3D Micro-XRF is a well established and none-destructive analytical method which has a wide range of fields for applications such as environmental science, archaeology, material science and so on. This kind of technique showed dramatic results in 3D image reconstruction, surface morphology and elemental depth sensitive profiles. Therefore, 3D Micro-XRF analysis method based on a confocal X-ray set-up is very suitable for evaluation and illustration with depth sensitive investigation of oil paintings. It is meaningful to characterize the surface elemental distribution in different layer depth by surface scanning. In this work, a 3D Micro-XRF experimental set-up is established based on a Mo target X-ray source. The operated voltage is 20kV and the currents is 0.5mA. The core optical components, two polycapillary X-ray lenses were designed and manufactured by the Key Laboratory of Beam Technology of the Ministry of Education, Beijing Normal University. The FWHMs of the confocal volume is 33.0 mu m , 32.4 mu m and 35 mu m in three dimensions, respectively. With a proposed progressive approximation method, a modern oil painting segament was anlysed using 3D Micro-XRF spectroscopy. The surface elemental distributions were mapped through surface scanning in different motor steps. This investigation can be referred for furture works that attempt to answer for questions on painting techniques, pigmant palette, production process, counterfeit identification and so on.