When I joined Diamond Light Source three years ago as a technical writer, I was really excited about having access to such a major physics toy, having spent seven years as a research scientist and then writer for the National Physical Laboratory. It’s been quite a surprise to find myself a whole host of other disciplines, from structural biology, geochemistry, environmental science, and the burgeoning area of cultural heritage.
So today sees my first live-blogging attempt, coming to you from the UK Synchrotron Users meeting. I’m currently listening to a seminar on Gothic Alterpieces, part of a Cultural Heritage session. The subheading for this session is “How Time Also Paints”, and looks at how certain paints and pigments can change with time, on both macro- and microscopic layers. This has been studied by using infrared spectroscopy to look at lead carboxylates, present in the egg tempera based paints commonly used on Gothic alterpieces.
Our next speaker is Sven Schroeder from the University of Manchester, who is talking about Non-destructive XAFS Microanalysis and Historic Prussian Blue Pigment. Prussian Blue was a pigment widely used in the 19th Century, perhaps most famously in Turner’s Blue Rigi. This group have been using synchrotron X-ray Absorption Spectroscopy (XAS) to look at different gaesous environments to look at how the pigments fades in situ. They’ve also carried out microanalysis of samples on paper, and seen significant differences between different historic Prussian Blue pigments.
Now we’re looking at copper and bronze corrosion. Instead of conventional XAS they are trying something called Optically Detected XAS (ODXAS), which should provide improved surface specificity. The results with ODXAS are comparable to conventional XAS, but there is currently more noise. If this can be resolved, the future does look promising, and has potential for time-resolved studies.
Now we have a shovel from a local Bronze Age site. Made of wood, the shovel was found by a miner in 1875 at a place called Alderly Edge, which then disappeared for more than 70 years. It was rediscovered by a schoolboy Alan Garner in 1953, but it took another 40 years for it to be correctly identified as an early – mid Bronze age artefact. But why did this wooden shovel survive?
Studies at the SRS synchrotron showed quite a lot of copper and arsenic. One of the scientists noticed the similarity with modern wood preservatives. EXAFS studies looking at the Copper K-edges of the shovel compared to a modern wood treated with preservatives, although with less arsenic!
The last talk of the day is on The Art and Science of Egyptian Faience: the case of the Step Pyramid tiles. These pyramids contained thousands of tiles – the first evidence of mass production in the ancient world. The tiles come in a range of blue and green colours, which can be traced to the amount of copper present in the glass phase (blue), but there is more debate over where the green comes from. This study looked at the glazing method (effluorescence), production methods and deterioration phenomena. Mapping the element distribution in the tiles has given some insight, but this was a pilot study, so more work is needed here.
There were further talks on the Friday morning, but I will need a bit more time to post about those!
Fascinating report, thank you. I have featured it on the Nautilus NN round-up (for authors) this week.
PS I have done the odd synchrotron experiment (fibre diffraction) at DESY, but this dates me a bit!
Hi Maxine. Yes, I would be interested to know how many other out there have been to synchrotrons at some point in their scientific careers, I’m sure the numbers are quite high!
I for one have been and still go. In fact I was at Diamond on the 1st Sept for the opening of Diamond/Imperial Membrane Protein Lab.
It was my first chance to see the facility – I hope it won’t be too long before we have a chance to make use of some of the photons. I loved the architecture of the place – it looked like a gigantic silver space-ship had landed in the Oxfordshire countryside!
It is an iconic building, although don’t get me started on the heating/cooling systems!
Do let me know if you get beamtime though…
A gigantic silver spaceship, yesterday.
Sara – There is a long history of work in the Science based Archaeology unit in Oxford using non-destructive methods to characterize and provenance articles. Synchrotron sources have the advantage that they do not require vacuum exposure (unlike electron beam microanlysis). I think the Oxford group did some work on pigment identification using a PIXE facility. As you are cloe to Oxford it might be of interest to check them out – my contact is Peter Northover in Materials.
That’s interesting, I’ve not come across that group. I’ll make enquiries, thanks Brian!