This morning, at about 9:55 CERN time, the LHC beam was dumped on a
collimator just upstream of CMS. This is when we first saw for the
first time the beam activity in the detector, a picture is attached.
What you see is the debris of the beam particles hitting the collimators. The resulting shower then produced a lot of activity in our hadron calorimeter (blue) and some hits in our muon system (small green rectangles). And all of those dirty messy particle showers from three different angles, which is why we have three different figures for the same events. The inner detector was turned off due to the beam still being very unstable and it can actually be damaged easily by randomly flying particles.
I am so excited! I am currently in the CERN media center where things are buzzing with journalists from all over the world! Before I forget to brag about the fact that the google home page is LHC themed today!