MACRO-XRF elemental maps of Scream (1895)

The MA-XRF maps of this version of the Scream have been aquired during a MOLAB campaign, as access granted by IPERION CH facilities, for the project: TECH_SCREAM_TECH – TECHnical Study of CoRE Art Materials & TECHniques of  SCREAM versions (research group from Munch museum, led by Irina Sandu).

MOLAB offers access to two scanning X-ray fluorescence (XRF) systems for micro and macro multi-element mapping of surfaces in a non-invasive manner. Elemental distribution maps at different spatial scales are of great interest for heritage science applications and particularly in the examination of paints and inks in ancient paintings and historical documents.

X-rays are highly penetrating and generally allow to non-destructively probe the entire painting stratigraphy. Hence the registration of elemental maps in a wide atomic number range (Z>12) allows for the investigation of the pigment use by the artist and for studying the historical evolution of the paint, also revealing hidden paint layersin the case of pentimenti, retouchings and over-paintings etc.

Macro-XRF scanning

The macro-XRF scanning systemfrom XGLab is equipped with a compact measuring head composed by a high efficiency X-ray generator source with an Rh anode (50kV and 200µA) and by a large area Silicon Drift Detector (SDD) (50 mm2, energy resolution of 130eV at MnKα) which allows for fast and sensitive multi-elemental analysis. An integrated video microscope camera is used to control and select thearea under investigationwhile two point lasers allows for exact point positioning at a measuring distance of 10 mm.The measuring head is mounted on a motorised frame with an X-Y-Z stage with continuous movement for mapping application.To this purpose the X-ray beam can be collimated on the sample surface with spot diameter of 0,5 or 2 mm to collect maps with dimensions of 5×5cm2 with 0,5mm of resolution or 45×60cm2 with 5mm of resolution, respectively. A fast digital electronics has been specifically developed for mapping application acquiring spectra for each pixel. A dedicated software is used for multi-element map reconstruction