I’ve been here since 23.45 and everything is running smoothly – we have had protons passing through our detector, clockwise round the LHC ring, more than 11,000 times a second. We are finding, usefully, that there are not very many beam-gas interactions (the events where protons collide with gas particles in the beam pipe). This shows us that the vacuum in the beam pipe is very good – not very much in there to interact with! Once we are colliding, any beam-gas events that we get while waiting for a proton-proton interaction will have to be thrown away, so it is positive that this background is low. However, the few signals we are receiving are being used as we speak to check, for example, timing between the different triggering detectors (the detectors whose signals will tell us whether or not to keep an event). As the Central Trigger Processor shifter, my job for the moment is to continue monitoring, making sure detectors are taking data normally. I am impressed with the number of people here at 2am with fresh and excited faces, working hard and feeling positive.
