A few days after the first LHC collisions, I dug into our growing dataset and made an animation from the signals we captured in the CMS detector of muons from LHC beam-halo events. The result looks like a computer simulation, but these are real measurements from the detector, observations from 10:33-10:42 PM Geneva-time on September 11, 2008. In that sense, it’s a live video. During this period, LHC beam #2 circulated for 9 minutes, 6 million times around the ring without getting off track. All the cheering on September 10th was about getting the beam to go once around the ring without getting off track.
The animation can be found at the bottom of the CMS Media page.
Red dots are the signals in the detectors, yellow lines are the best-fit curves through them, representing the path taken by the muons. Notice that the muons are more often vertical when the beam is off (because they’re cosmic rays) and horizontal when the beam is on (because they’re from proton collisions with gas atoms and collimators far upstream in the LHC). The rate also increases dramatically.
Ego-boosting update: when Jim Virdee, the CMS spokesperson, presented the experiment to a group of VIPs including the French Prime Minister, he used my animation (not shown in this picture, but I am told that he did). I’ve been asked what he might have thought of Big Bird.
The Everything Seminar 
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