I was on shift all week at ATLAS. When I signed up for these shifts, I thought perhaps we would be looking at collisions, but well, things weren’t quite that exciting. Actually, for me they weren’t that exciting at all since I was at the Liquid Argon Calorimeter desk, and our detector wasn’t being read out for most of the week. This was to allow ATLAS to write out more data in a short time. The calorimeter data volume is quite large and our calorimeter wasn’t the focus of these studies. Seth was sitting at the Pixel desk, and things seemed a bit more interesting there as they were recording lots of tracks.
ATLAS was recording cosmic muon data this week. I heard there were at least 50 million events recorded, some with the magnets on and some with the magnets off. This will be extremely useful for calibration and alignment. The data with the magnets on will contain information about muons turning as they are influenced by the magnetic field. The momentum of these muons can be calculated and compared to expectations as a nice cross-check. The data with the magnets off will contain muons that don’t bend, and therefore draw straight lines through the ATLAS detector. This is useful for checking the alignment between different detectors.
As of Thursday night, ATLAS is taking data with the entire detector writing out data, and will continue like this for the rest of October. This will probably be the best data we have taken yet. It can be studied for a few months to have us in really great shape for next year’s running with collisions.
After November 3, we won’t run much with the full detector until next year. The detector will be opened up and people will be allowed in for maintenance, things like repairing or replacing problematic power supplies and malfunctioning pieces of electronics.
