We had a little drama this morning changing samples. I was about to say to my colleague, 'At least we haven't had any sample changeover problems this time' when the sample got a little bit stuck and was in danger of falling off. After a bit of panicked yelling to move things around, we managed to rescue the situation and continue as normal. Phew!
The reason I'm writing this - and yes, it has no relation so far to the title of this post, but just hold your horses - is because to fix this you would usually call the beamline scientist. The problem with that is it was 5:30 in the morning. And although I've managed to pick things up fairly quickly on how to use the vacuum system and operate the various detectors, I'm a long way from being an expert on this particular beamline.
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Flash back to last week, when I was working with some other colleagues on the small angle X-ray scattering (SAXS) beamline, looking at milk. On our last day of beamtime, at about 2:00 in the morning, I managed to break a very thin silicon nitride window that was keeping the detector chamber under vacuum.
The frame on this window is 10 x 10 mm, the window is about 1000 nm thick (0.001 mm) and 5 x 5 mm square. The one I broke was about half the size of this (and therefore costs about twice as much).
As we had been told to do if this sort of thing happened at 2:00 am, we called the control room to help change to a new window for us. Fortunately (?) a window had broken earlier in the experiment, and the beamline scientist fixed it, briefly telling me what he was doing along the way. So when it came to turning the vacuum pump back on, I was able to show the control room people which pump it was. But after that it was all up to me to get things back to how they were.
One thing that is important is to make sure that all of the beam is going through the window. I took a few scans and realised that the window was not centred. The day before, the beamline scientist had pointed out what to look for in the video camera image when centering the window, but when I had to do it by myself I had no idea what I was looking at. After moving it by brute force and getting nowhere (apart from quite frustrated), I resorted to a more systematic approach of turning each dial separately, half a turn at a time, and taking another scan (meaning having to activate the 'hutch close procedure' each time). In one direction moving the window, I think I had about ten scans before things started to improve. By this stage it was 3:00 and I was getting really irritable. In fact at one point when I went into the hutch to do another half-turn of the dial, I must admit that I had a bit of a cry. At this point I had had a total of about 9 hrs sleep in the preceding 69 hours. My colleagues were playing music that was annoying me, and sitting around chatting. I was annoyed at them for not helping, which was completely irrational because they weren't able to do anything at this point. I couldn't delegate this frustrating job to anyone - if we wanted to collect data, I had to fix it. And at that moment, I almost wished that I didn't know what I know about beamlines and synchrotron stuff, because without that knowledge we could all go to bed, lose a few hours of beamtime, and that would be it until the beamline scientist came in and fixed it - and that was probably what any other user group would have done.
Thankfully a few half-turns later, then a few in the perpendicular direction, the window was in the right place and we were able to carry on with the experiments (and I was able to go to bed). But I don't think I've ever been that frustrated, while being that tired, with something before. (Although maybe after the Oxfam trailwalker, when they wanted us to walk up steps onto a platform to receive our medals after we crossed the finish line. I refused.)
In the end the milk experiments worked really well. We got through everything we wanted to and should get a few papers out of it, and a few ticks in various administrative boxes for our funding arrangements. The ZnO experiments have thrown us a bit of a curve ball, but we should still be able to get something useful out of them.
[Translations for any of my American readers:
"turns to custard" = goes wrong, goes bad.
"hold your horses" = wait a minute.
The SAXS beamline
