If the LHC folks had managed to get one proton to go around the 17-mile tunnel once yesterday, CERN would have declared it a huge success. Well, by the end of the day they sent a beam of protons around the ring hundreds of times. I’d say they blew away expectations!
At ATLAS today, everyone was gushing about yesterday’s success, and about the data we had in our hands. The LHC people decided to put a collimator in front of ATLAS yesterday for several hours, resulting in numerous showers of particles lighting up our detector like a christmas tree. In the calorimeter data, we see energy in these events in just about every one of the independent 200,000 cells (each makes its own measurement of energy in a small region). Other detectors have similar luck. With this we can do a lot of work fine tuning and calibrating our detector, to be ready to take full advantage of proton-proton collisions, whenever they come. This by the way was supposed to be maybe a month or two, but with the way the LHC is working, we better be ready by about next week.
Also, here are some cool event displays from ATLAS.