Step into my office...

Welcome to my newly established field lab/office/rainy-day-busy-work-space. OK, so my new office is a corner of the room, but it's my little lab and I'm proud of it. Today I spent the whole day analysing ceramic objects with portable X-ray Fluorescence Spectrometry (pXRF). This is an analytical technique which I specialise in using, and I've been itching to get on with the analysis ever since the instrument arrived last week. pXRF uses X-rays to excite the atoms in sample. Each chemical element has a characteristic fingerprint unique to that element. This instrument detects the chemical fingerprints in the sample and we can then identify what elements are present in the sample. The technique is non-destructive, which makes is very popular in archaeology. Today, I completed almost 200 measurements. This is another reason why this technique is popular, it can generate data very quickly. However, processing that data will take time. I have yet to start that part. So far, all the ceramics I have analysed have come from the excavation itself, but cover a variety of historic periods. This is because we want to see whether the clay used to make the pots found in the La Poterie region changes over time. Or, if a different cultural group used different clay as well as having different pottery styles. In the long term, this work will complement the clay surveying that I have been doing with Loe. If we can locate workable clay in the area, we can try and compare the chemical composition of the clay with the chemical composition of the ceramic objects.

Of course, another reason why I really like working with the pXRF is because it looks like something out of Star Trek. Posing with the pXRF (Charlie's Angels style) is almost always the first thing people want to do. We're also planning to take the pXRF over to St. Vincent for a few days to analyse some pots in a museum there. I should also point out that I can use this instrument in handheld mode too (i.e. not relying on the stand and the laptop), but although it is portable, it can get heavy, especially when you need to hold it still for c. 60 seconds. So I prefer this set-up.

Ceramics can be particularly tricky to analyse, for a start, the shape is problematic. Ideally we want a flat sample, since pots are rarely flat, I have to find a way to balance the convex surface on the detector (and the sample table is not always helpful). Also, the humidity here is problematic, which is why in the top picture you can see a couple of sample bags filled with dried rice. These have holes punched into them and I put these in the box with the instrument when it's not in use to try and absorb any extra moisture. Rule one of having a field lab: learn how to jerry-rig your equipment.

I think I have another couple of days worth of analysing to do, and then it'll be time to process the data. So stay tuned for more pXRF updates.