Monday, 24 September 2012

Diamond trip day 5: Using chocolate bars as bouyancy aids

Our time at the Diamond labs. has finished for now. What have we learnt over the last 5 sleep deprived days? Well, we have found what we were looking for in the granules. Earthworms secrete balls of calcium carbonate - CaCO3. Calcium carbonate is an interesting mineral as it can occur in a variety of different forms which differ in the way that the calcium and the carbonate are arranged relative to one another. The earthworm granules are perculiar as the different forms of calcium carbonate all occur together. Over the last five days we have tracked down a particularly rare form of calcium carbonate known as amorphous calcium carbonate. Normally this stuff converts into another form of calcium carbonate - either calcite, aragonite or vaterite - but in the earthworm balls the amorphous stuff is incredibly stable. Now that we've found the amorphous calcium carboante we can start trying to work out why it is present and why it hasn't changed into a more stable form. This may (ultimately) have industrial applications in terms of controllng calcium carbonate crystallisation which could feed into all sorts of things such as the use of calcium carbonate in pigments and preventing the precipitation of calcium carbonate in pipes causing pipe blockages.
Paul and Fred changing the sample on Beamline I18

Perhaps more importantly we have learnt the difference between baking and roasting and also that Aeros float and Mars bars sink. Whilst Crunchies float initially, over time the honeycomb dissolves and the chocolate casing then sinks. Important information if ever you find youself  thrown overboard with a choice of chocolate bars to use as bouyancy aids!

Sunday, 23 September 2012

Diamond trip: Day 4

Back to the beamline by 9.30 after finishing last "night" at about 2 a.m. We finished the night before at about 1 a.m. and had to getup at 3.30 a.m. to change sample the previous morning (or night). I'm definitely starting to get synchrotron head. The Ca XANES map we set up last night (actually 2 a.m. this morning) had almost finished by the time I got here this morning - a massive data set but probably all calcite which is rather dull when you are looking for other forms of calcium carbonate. We're now doing a few Ca XANES spots for detail and will then go on to run some diffraction standards. Then we have a final granule to XANES map and after that we'll probably try and return to some of the ACC identified in previous granules to do some EXAFS. We should get all this done before setting up a final overnight run this evening.
The long lonely corridor outside the beamline at night.

Looking across the "roofs" of the experimental hutches at Diamond.