On Tuesday, following a tip-off from Maxine, Richard noted the passing of the Daresbury Synchrotron in Cheshire, which shut down finally in August. This gave me pause for quiet reflection since I had been a Daresbury user since 1991, cutting my teeth as a crystallographer by spending long nights in the darkroom developing the film packs that we used to record the X-rays scattered by our crystals.
More often than not we would come away pretty satisfied with the outcome of those long hard nights. Sometimes we had more than 48 hours of beam-time to sweat through and would struggle home with a kind of jet-lag having worked odd hours of the night and day. I remember on one trip (when I was running a group of one – yours truly) working a 48 hr stretch entirely on my own. By that time they had at least made the switch to electronic detectors which you could leave running on automatic for the hours needed to collect the data – so I could get some snatches of sleep.
However, these days the introduction of CCD detectors means that you can grab your data in as little as 30 minutes, so the turnaround time between crystals is much faster and there is little time for a break. That’s assuming that your crystal diffracts X-rays in a nice orderly fashion – more often than not, instead of orderly ranks of spots, you see a few irregular black smudges – and that means only one thing: next crystal please!
So trips to Daresbury were never easy or relaxing – there was plenty that could go wrong, not just with our crystals but also with the machine, which every so often would decide unceremoniously to dump its current of electrons, turning off the X-rays that were probing the innards of our proteins. But along the way we still got plenty of useful data to kickstart quite a few structural projects. We even have a few structures determined using Daresbury data that are still to be published (manuscripts in tardy preparation) – as, I imagine do other groups – so we haven’t yet heard the last of the Daresbury synchrotron.
Yet as Daresbury flickers and fades a new X-ray source has ignited in the middle of the Oxfordshire countryside. The Diamond Light Source is now open for business and, co-incidentally, I was there yesterday helping to chaperone a group of UG and PG students from Imperial who were visiting for the day to discover what a real synchrotron looks and feels like.
Diamond is a truly impressive facility – a massive, gleaming donut of a building. It reminded me of my favorite quotation from Homer Simpson which I have pinched for the title of this piece. It is also the workplace of NN blogger Sara Fletcher with whom I was delighted to catch up yesterday and who will no doubt tell us more about life at Diamond in blogs to come.
The curved experimental hall contains a huge concrete tunnel that houses the accelerator or ‘storage ring’. The ring is basically an evacuated pipe, a few cm in diameter that is surrounded by radiofrequency cavities to keep the electrons whizzing round at close to light speed and magnets to steer them through the ring. Every so often a magnetic insertion device causes the electrons to shimmy as they pass. This electronic wiggle releases a burst of intense X-rays down the beam-line and into the sample – which in our case is a tiny crystal of proteins, often no more that 0.1 mm in size. The beam-lines fan out tangentially from the ring – at present there are about 20 of them.
But I’m getting way too techie. While I wipe the flecks of foam from my mouth it will suffice to say that with Diamond the good work of X-ray analysis initiated at Daresbury will continue. The torch has passed and fortunately is brighter than ever!
Oh, and one more thing. I was pleased to see that the section of the storage ring that we visited was housed in “Zone 13”:
Last week I spent several nights in a hotel that had no room 1013 on the 10th floor, presumably as a sop to the superstitious. It is good to report that no such nonsense is tolerated at Diamond!