ATLAS Tier 2

Atlas Detector ATLAS is an international collaboration of scientists currently building a particle detector that will probe nature at the TeV energy scale. The ATLAS detector (show in the opposite figure) will study proton-proton collisions at a center of mass energy of 14 TeV that will be provided by the Large Hadron Collider, LHC, now beginning its operation at the European Laboratory for Particle Physics, CERN .

Atlas Event The LHC has begun colliding protons in November 2009. The image shown is one of the first events recorded by ATLAS in December 2009. The particle physics group at the University of Victoria has been an active member of the ATLAS Collaboration since its inception in 1992.

The ATLAS detector is expected to produce tens of Petabytes of data per year. ATLAS and the other CERN experiments have adopted a distributed or grid computing model for the analysis of the data. The system is called the World Wide Large Hardron Collider Computing Grid (WLCG) and includes facilities around the globe.

The model has a tiered structure with the central Tier 0 facility located at CERN for recording and managing the raw data. Ten Tier 1 centres are distributed around the world with one site located at the TRIUMF Laboratory in Vancouver. The Tier 1 centres are responsible for processing a fraction of the raw data and producing data sets for analysis. Scientists use the Tier 2 facilities for their studies.

Canada hosts two WLCG Tier 2 sites: one in Eastern and Western Canada. The Western Canadian site includes computing resources at the University of Alberta, Simon Fraser University and the University of Victoria.

The UVIC facility uses the Research Computing Facility which has been in operation since 2002.