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ALICE Data taking status

ALICE Data taking status. Lee Barnby. Outline. Introduction to ALICE Experiment Physics Programme 2009 Data Taking Detector performance 7 TeV Data Taking Latest news A UK Perspective. ALICE Detector.

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ALICE Data taking status

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  1. ALICE Data taking status Lee Barnby L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  2. Outline • Introduction to ALICE • Experiment • Physics Programme • 2009 Data Taking • Detector performance • 7 TeV Data Taking • Latest news • A UK Perspective L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  3. ALICE Detector Cut away view showing central barrel inside L3 magnet (red) and muon tracker to the right. L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  4. Particle ID capabilities L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  5. ALICE Physics Programme • Primary ALICE purpose is to study quark-gluon plasma via heavy-ion collisions • Original plan for √s=5.5 TeV per nucleon collisions • Now 2.75 TeV for obvious reasons • 14/5.5 is A/Z for 208Pb • Few (4?) weeks of Pb+Pb running envisaged for late Autumn • ALICE goal is to collect 1 x 108 Pb+Pb events L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  6. QGP observables • Initial measurements to characterise system • Dynamics (expansion) through differential measures of hadron spectra, interferometry • Detailed measurements of properties • Jet quenching / modification in QCD medium • Direct photons • Quarkonia disassociation L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  7. ALICE Physics Programme: p+p • 1st question: Why? • LHC marks the first time that energy frontier for p+p and A+A is advancing at the same time • Eg RHIC provides 200 GeV collisions since 2000, previously achieved with SppS in 1980s • Therefore need baseline/reference data • OK, energy is higher but we prefer to interpolaterather than extrapolate • ALICE best suited to measure aspects of particle production (soft QCD) in p+p due to • Low field (0.5 T) thus low pT reach • Particle ID capabilities (hadronic and EM) • Low material budget (X/X0 ~ 7%) L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  8. ALICE Physics Programme: p+p • What? • Large minbias sample needed, nominally 109 events. We need sufficient stats to compare to 108 Pb+Pb events • Triggered samples to get better stats for some measurements • Electron trigger (heavy flavour) • High multiplicity p+p events • EMCAL (jet patch) • PHOS (photons) L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  9. 900 GeV Run Statistics • 1st collisions recorded 23/11, continued through 15/12 • ALICE recorded ~1 M events • 500k are ‘good’ events • 100k with field off for alignment • Also 40k at 2.36 TeV L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  10. 900 GeV Detector Performance TOF L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  11. 900 GeV Detector Performance TOF L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  12. L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  13. More 900 GeV plots Conversion photons - radial Conversion photons – x-y L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  14. 900 GeV more statistics • 430 GB raw data – we store 2 replicas (860 GB) • RAW data processed in 6 passes • Due to debugging of both detectors and code • Eg many updates to online conditions database • We store 3 copies of reconstruction output, currently 330 GB • Currently working to reduce this since it works out 115% of RAW • Eg have to stop saving reconstructed points for all events L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  15. 7 TeV Data Recorded Events recorded since 30 March Minbias event rates L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  16. 7 TeV p+p event in ALICE 7 TeV event L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  17. Another 7 TeV event L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  18. Yet another view L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  19. 7 TeV Outlook • Goal is to collect 1.0 x 109 minbias events • In first two weeks we collected 1.0 x 107 ie 1% • BUT this is utilising only one bunch crossing (BX) • A modest increase in the number of colliding bunches would allow ALICE to reach its goal • Continued running for rare triggers depends on limiting luminosity increase at P2 (ALICE) • TPC is limiting factor • Number of overlaid events from one BX • Past and future events during the drift time L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  20. UK Perspective – RAL T1 • ALICE production jobs run at RAL • Small fraction of integrated time but noticeable spikes ALICE Jobs in red L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  21. ALICE jobs on various timescales 1 year 3 months Lots of bursts of activity around Christmas holiday for raw data pass and recently for first pass at 7 TeV 1 month L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  22. L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  23. RAL T1 is important to ALICE 2 months L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  24. RAL T1 is important to ALICE 6 months L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

  25. Conclusion • We are taking data! • There is a lot more to come. • Pass 0 RAW reconstruction is completed within <24 hours • Pass 1(+) reconstruction at T1 sites • We are looking forward to Pb+Pb data later this year L.Barnby@bham.ac.uk - GridPP24 ALICE Data Taking Status

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