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Results from the SPD test beam data analysis D. Elia, R. Santoro (Bari) PowerPoint Presentation
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Results from the SPD test beam data analysis D. Elia, R. Santoro (Bari)

Results from the SPD test beam data analysis D. Elia, R. Santoro (Bari)

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Results from the SPD test beam data analysis D. Elia, R. Santoro (Bari)

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  1. Results from the SPD test beam data analysis D. Elia, R. Santoro (Bari) • Look at the proton/pion beam data: • test beam setup • clustering analysis • alignment • resolution studies ALICE week / Offline meeting - March 15, 2004

  2. SPD Testbeam Setup (In-beam) Half stave Pb-Target Mini bus 1 beam Middle plane Mini bus 0 Table MWPC Scintillators Quartz Table: 150 cm 2003 Beam Test Setup (I) • 158 GeV/A In ion beam ≈ 104 ions/spill (15 days) Pb target 4mm thick • 120 GeV protons (3 days) ALICE week / Offline meeting - March 15, 2004

  3. 2003 Beam Test Setup (II) • Target: 4 mm Pb • Trigger: quartz counter (beam) + 2 cm x 2 cm scintillator (interactions) • Mini bus 0, 1: 2 singles chip for mini bus mounted in crossed way to have the short pixel size in X-Y direction • Middle plane: single chip under study • Half-stave read out through MCM including optical module • 2.8 GB of data collected Middle plane Half-stave Target Mini bus 0 Mini bus 1 ALICE week / Offline meeting - March 15, 2004

  4. Proton data samples/setup • Data taken with 120 GeV/c proton/pion beam: • Setup • Focussed and wide beam data available ALICE week / Offline meeting - March 15, 2004

  5. Hit maps (focussed beam) ALICE week / Offline meeting - March 15, 2004

  6. Hit distributions ALICE week / Offline meeting - March 15, 2004

  7. Cluster analysis (I) • Cluster definition: • group of fired pixels • sharing a common • side ALICE week / Offline meeting - March 15, 2004

  8. Cluster analysis (II) • Cluster size: • number of fired pixels • in the cluster ALICE week / Offline meeting - March 15, 2004

  9. Cluster analysis (II) • Cluster size: • number of fired pixels • in the cluster • Cluster dimx,y: • x and y dimensions • of a box containing • the cluster: dimy dimx ALICE week / Offline meeting - March 15, 2004

  10. Alignment procedure (I) • Select events with 1 cluster in each of the minibus planes • Do alignment within each minibus by using best x/y coordinate for each of the planes Correlation plots for the 1st minibus ALICE week / Offline meeting - March 15, 2004

  11. Alignment procedure (II) Correlation plots for the 2nd minibus ALICE week / Offline meeting - March 15, 2004

  12. Alignment procedure (III) Correlation plots minibus planes aligned ALICE week / Offline meeting - March 15, 2004

  13. Alignment procedure (IV) • Final step: alignment between the 2 minibus ALICE week / Offline meeting - March 15, 2004

  14. s(x) = 110 mm s(y) = 21 mm Resolution study (I) • Select events with 1 cluster in each of the minibus planes • Apply least squares fit by using the 4 minibus planes points with proper weights • Calculate residuals on middle plane: ALICE week / Offline meeting - March 15, 2004

  15. Selecting cluster size = 2 on middle plane: s(x) = 42 mm s(y) = 20 mm Resolution study (II) Selecting cluster size = 1 on middle plane: rms(x) = 127 mm s(y) = 21 mm ALICE week / Offline meeting - March 15, 2004

  16. What next • Better understanding of alignment and resolution(geometrical simulation available) • Cluster analysis vs: threshold/bias/angle scans • Efficiency studies vs: threshold/bias/angle scans • Look at the HI data ALICE week / Offline meeting - March 15, 2004