Work Package 8 (WP8): Cultural Heritage

Ion Beam and XRF Techniques for Cultural Heritage Studies

Objectives and intended results

1. Upgrade of the experimental of the external ion beam set up. Specifically, the upgrading will include an integrated data collection and processing system that will control the movement of the specimen support in four directions (X-Y-Z-phi), large area new tech (silicon drift) x-ray detectors, Sample changer that can operate at a constant speed of up to 100 mm/s. The upgraded CALIBRA external ion beam set up will offer the possibility of combined measurement with the PIXE, RBS, PIGE techniques in large material surfaces of cultural heritage objects and in a relatively short period of time. Via these analyzes the mapping of the distribution of the main, minor and trace elements on the analyzed surface with a spatial resolution of 0.8-1.0 mm will be achieved. The use of the new experimental external ion beam set up to cultural Heritage materials / objects is expected to provide important new information regarding the 3D distribution especially of relatively low Z elements such as Na, Mg, Al, Si, P contributing to understanding the processes related to surface alteration / erosion etc.
2. Development of a new XRF Portable Spectrometer (MA-XRF) for on-site analysis and scanning of large surfaces of about 1 m² in a short time of a few hours (~ 2hr) with adjusted spatial resolution rate depending on the application from <0.05 mm (Micro-) to about 0.5 mm (sub-mm). The application of this technique especially in the study of polychromy on ceramic sculptures, paintings and frescoes will allow safer interpretation and visualization of the objects targeting in a more accurate digital integration of the results which will allow the reconstruction of the original / authentic drawing.
3. Upgrading the micro-PIXE technique by applying the confocal geometry. This new one analytical capability will provide 3D elemental analysis on micro-regions of interest, and in particular in cases where there is either erosion stratification on the surface under consideration or stratigraphy that originates from original construction technique. In such cases, it is important that the detection – identification of underlying layers is non-invasive. The added value of the setup is apparent when compared to other non-destructive techniques where the surface layers is opaque to both visible and infrared radiation.

Tasks to implement

1. Supply of the required upgraded instrumentation for the experimental layout of the external
   ion beam as well as new equipment for the portable MA-XRF spectrometer
2. Mechanical precision design for positioning and optimal layout of detectors and other auxiliary systems / instruments in the external beam set up. Mechanical design of the head of the MA-XRF spectrometer. Mechanical Design of Focus Lens Adapter the X-ray detector and the Alignment Assistant.
3. Precision structures for the X-ray detector bases in the external ion beam set up and other auxiliary mechanical devices, adapters and aligners for application of the confocal micro-PIXE (3D-MicroPIXE).
4. Calibration of the external ion beam set up for quantitative elemental analysis via application of PIXE, RBS and PIGE techniques. Evaluation of the calibration by comparing the analysis results of standard materials that resemble the composition of archaeological / historical objects with the corresponding reference values
5. Calibration of the MA-XRF spectrometer so that it can generate quantitative distribution maps of the major, minor and trace elements on the surfaces of archaeological objects. Evaluation of the calibration by comparing the analysis results of standard materials that resemble the composition of archaeological / historical objects with the corresponding reference values
6. Development of the alignment and calibration methodology of the experimental configuration of the confocal micro-PIXE. Study of the characteristics of the confocal geometry as the dependence of the spatial resolution in relation to the energy of the detected characteristic X-ray.
7. Applying confocal micro-PIXE (3D-MicroPIXE) to the analysis of corroded ancient glass, glass mosaics, metal sheet mosaics, glazed ceramic samples
8. Use of the experimental external ion beam set up in the analysis of coating layers and industrial dyes that have been used in historical objects, in the study of tools from the Byzantine collection of the Benaki Museum, the characterization of polychromy from wood paintings from Hellenic-Roman Egypt, but also in the study of ceramic mosaics from the Classical Period
9. Application of the MA-XRF portable spectrometer in the study of the remaining polychrome on sculptures, decoration in ceramic vases, paintings in wall-painting fragments and in the study of patina / corrosion layers of copper alloys from ancient antiquities

Outputs (Deliverables)