… since yesterday! The LHC has first circulating beams in both directions again …

I almost forgot … after about two months of hibernation the ATLAS Detector is back in business waiting for the LHC to come up, meanwhile entertained with cosmics data taking. The big ring will probably start up somewhat next week …

Believe it or not, but the LHC made it into the Vanity Fair magazine!
Next to ads for expensive wrist watches and pictures of (half) naked women, there is a four pages article including pictures of posing head scientists … what’s next!?

Today ATLAS has recorded the first collision events at 2.36 TeV.
Still far from the design energy of 14 TeV but already 400 GeV more than the previous best collider, the Tevatron. Also a bit later than I suggested in a previous post, due to some problems last week.
In the plot you see one of the first 2-jet events taken. The lower right inset shows the energy distribution in the eta-phi plane (something like a rolled-out detector).

… for the first time! Since the innermost par of ATLAS needs special and safe beam conditions the pixels have been of during the previous test. Today the LHC was/is running stable with 4 bunches per beam delivering collisions at 900 GeV (450 per beam) to all experiments.
Unfortunately there was a power cut last Wednesday so the previously mentioned surprise will have to wait …