I have been in the ATLAS control room on shift each of the last three weeks. Each shift was more boring than the last. The first collisions were on a Monday. I had shift that Tuesday. Tonight we actually had a first while I was here. We just had the “first time with two beams with 2 bunches per beam at 1.18 TeV.” Okay, there are a lot of qualifiers in there. But it was still exciting to watch the big screen in the control room that gives the status of the LHC as the beams were accelerated.
Two bunches of about 10 billion protons each were circulating in the LHC in each direction. The energy of each beam was slowly increased starting from the injection energy of 0.45 TeV, and we oohed and aahed as it went up. I took a photo of the big screen when both beams were up to 1.18 TeV (you can see the energy at the top in the middle, “1180 GeV”). Hopefully some time in the next few weeks we will get collisions at this energy!