ATLAS is a particle physics experiment at the Large Hadron Collider (LHC) at CERN.
The primary purpose of the detector
will be studies of the origin of mass at the electroweak scale,
therefore the detector has been designed for sensitivity to the largest possible
Higgs mass range. The detector will also be used for studies of top quark decays
and supersymmetry searches.
ATLAS is one of the largest collaborative efforts ever attempted in the physical sciences with about 3000 physicists and engineers from more than 170 universities and laboratories in 38 countries.
After almost 2 decades of building, installation and commissioning, the ATLAS experiment became operational in September 2010, when the LHC beams were circulated for the first time producing splashes of particles in the detector.
The LHC produced the first proton-proton collisions at 0.9TeV and 2.36 TeV in late 2009.
Since March 2010 ATLAS is recording beautiful data from collisions of 7 TeV and producing the first interesting physics results.