The Control Room is quiet. The configurations are set. The trigger menu is uploaded. The shifters are ready. All that is left is for the LHC to deliver beam.
Pretty soon the ATLAS Control Room will be filling up with experts, managers, shifters, and other fellow collaborators as the LHC begins to deliver 10 beam splash events from both beams (10 from beam 1, followed by 10 from beam 2). A beam splash is when the LHC steers the beam into the beam collimators just upstream from ATLAS. This creates of splash of muons, pions, protons, and whole bunch of other junk that basically lights up the entire detector all at once. It is literally a spray of particles. Hence the term "Beam Splash". This will be the third time that ATLAS has gotten beam splash events. The two previous times was when the LHC had previously turned on. Once in September 2008, once in November 2009. So this is an old bag for us now. This is a unique opportunity for the detector to check its timing and is the first big step for commissioning the detector before the LONG 2010/2011 LHC physics run.