The application of confocal depth-resolved micro-X-ray absorption spectroscopy to study colorant copper in ancient lead-silica glassy system at the Beijing Synchrotron Radiation Facility

Abstract

A new mobilizable confocal fluorescence end-station for depth-resolved micro-X-ray absorption spectroscopy being setup with optimal settings and applied to copper in lead-based glaze and pigment of ancient Chinese ceramics. The major equipment of the confocal micro-spots system included two polycapillary half-lens: one is defines the incident beam path and another polycapillary half-lens at 90°defines the probe sample volume, and operate with an efficient automatic alignment program by evolutionary algorithm. This depth-resolved system was examined on a general X-ray absorption spectroscopy (XAS) beamline at the Beijing Synchrotron Radiation Facility (BSRF, 1W1A/1W2B). The application in this case report that the status of copper in various lead-silica amorphous materials and speciation in different depth of lead-rich glassy layer from aged China. The results shown that this equipment working well and can obtaining equal data from surface to certain depth of copper colorant. Also, although the large number of lead component existing in the various glassy matrix but due to high-intensity of synchrotron radiation light and optimize-designed structure of facility, the results still revealing the preeminent ability of spatially resolution as well. As a mobilizable end-station with advantage, such as non-destructive and adjustable micro-spots, this confocal system in BSRF can improve the function and flexibility of general XAS beamlines, and indicating their capabilities to applicating to archaeological and cultural heritage field more deeply and widely in further.