丁香园AV

Synopsis

Archaeological archives all around the world are currently in possession of documents with an age of 1000 years and more, which can not be deciphered due to their age and fragile condition. Documents are usually very thin (layer thickness of about 0.1 mm) and are laid out in stacks or rolls with a spacing between individual layers of 0.1 to 0.2 mm. Their age and general condition makes it impossible to unfold or -roll them without causing damage. 

There is however a method to scan the writing on these documents without having to unfold them. 

These documents were written with ink or paint made from organic material used to write on material of similar composition (e.g. animal skins or papyrus). Therefore distinguishing between substrate and writing is very challenging, however, the ink used on some of these documents has been found to contain small percentages of lead (roughly 3000 ppm). 

By using X-ray beams with an energy of 88 keV or higher, the k-edge of the lead particles can be used to identify patterns of ink on top of the otherwise organic background.

This talk presents initial tests of ink on papyrus using X-rays, performed at the Canadian Light Source's X-ray beam line in 2022 and 2023.