1. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS SFU & Canada’s Role in ATLAS M.C. Vetterli Simon Fraser University and TRIUMF SFU Open House, May 31 st 2008 (With Dugan O’Neil)

2. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS Canada’s Role in ATLAS Accelerator: TRIUMF, in collaboration with Canadian industry, designed & built parts of the LHC Detector: Parts of the ATLAS detector that measure the total energy of the particles emerging from the proton-proton collisions Computing: High-performance Grid computing to analyze the data from ATLAS Physics: We are involved in just about all physics topics (no time to discuss all of this)

3. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS What do we Measure? In a Nutshell: - Proton-Proton collisions at the highest energy ever achieved in the laboratory - Look at what emerges & infer what happened - Structure & Dynamics Details? Measure the particles coming from the collisions - particle type (electron, proton, muon, jets, …) - direction/momentum - energy Simple in concept; complicated in execution

4. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS What do we Measure? - tracking detectors: measure space points & associate them to “track” the particles’ path through ATLAS  direction -magnetic field: bends particles  momentum, charge -“Calorimeters”: measure total energy of particles by absorbing them -muons: go through the calorimeters detected in outer region -neutrinos & exotic stuff: go through everything  invisible measured by what is not there!

5. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS The ATLAS Detector Canada built this Liquid Argon End-Cap Calorimeter

6. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS LAr TileCal 6

7. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS When protons collide we don’t get to choose what happens, Nature does in these proportions The Experimental Challenge Billiard-ball like collisions We select only events that look interesting, but we still need to collect a billion events per year! A million billion!! inelastic Events in one year @ initial operation Other known processes This is what we want: One event in 10 billion!!

8. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS The problem is worse because many of the background events look a lot like the Higgs Find the Waldo with a missing shoe in 40 million of these panels!!

9. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS It would take 4.5 Million CDs (a stack 10 CN towers high!!) to record one year’s worth of data, corresponding to about 695 years of music! An LHC Event We take electronic pictures of the collisions and we record 200 “events” per second on computer tapes for later analysis. Each event is 1.6 Mbytes  3.2 Petabytes per year! Need another ≈ 2.5 PB/yr to store secondary data sets. Collisions occur 40 million times per second!

10. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS The World-Wide LHC Computing Grid To deal with this avalanche of data, we have built an international “GRID” of high-performance computing facilities linked together by high-speed networks (lightpaths) These centres act as one huge system thanks to Grid “middleware” that coordinates job submission and data management Users submit jobs to the Grid and never need know where their job ran Users get access to MUCH more computing than if they used only in-house resources

11. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS

12. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS

13. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS The TRIUMF Tier-1 Centre Canada’s contribution to the first layer of ATLAS computing Funded by a grant to a consortium of universities led by SFU Currently has: 782 CPUs ≈1000 Tetabytes of disk (1 TB = 1000 GB) 560 Terabytes of tape (your desktop probably has 200-500 GB) By 2011, will have: > 2500 CPUs ≈ 4500 TB of disk ≈ 3500 TB of tape Also has a point-to-point network link to CERN in Geneva * Tier-2 centres in the universities (SFU is one of them)

14. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS Bring on the Data!!

15. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS Extra Slides

16. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS The ATLAS Collaboration  1800 physicists & engineers  150 universities & laboratories  34 countries ATLAS-Canada Alberta British Columbia Carleton McGill Montreal Simon Fraser Toronto TRIUMF Victoria York

17. M.C. Vetterli; SFU/TRIUMF Simon Fraser ATLASATLAS A Lesson from the Past? November 1989 This is what the web looked like in the beginning before CERN contributed the world-wide-web tools for free Impact of the Grid  The World-Wide-Grid has great potential - It can do for high-performance computing what the World-Wide-Web did for information sharing.