Results from the SPD test beam data analysis
Results from the SPD test beam data analysis D. Elia, R. Santoro (Bari) Look at the proton/pion beam data: Ø Ø test beam setup clustering analysis alignment resolution studies D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 1
2003 Beam Test Setup (I) ü 158 Ge. V/A In ion beam ≈ 104 ions/spill (15 days) Pb target 4 mm thick ü 120 Ge. V protons (3 days) SPD Testbeam Setup (In-beam) Half stave Pb-Target beam Mini bus 0 Mini bus 1 Middle plane Table Quartz Scintillators MWPC Table: 150 cm D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 2
2003 Beam Test Setup (II) ü Target: 4 mm Pb üTrigger: quartz counter (beam) + 2 cm x 2 cm scintillator (interactions) üMini bus 0, 1: 2 singles chip for mini bus mounted in crossed way to have the short pixel size in X-Y direction üMiddle plane: single chip under study ü Half-stave read out through MCM including optical module ü 2. 8 GB of data collected Target Mini bus 0 Middle plane Half-stave Mini bus 1 D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 3
Proton data samples/setup Data taken with 120 Ge. V/c proton/pion beam: § Setup § Focussed and wide beam data available D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 4
Hit maps D. Elia, R. Santoro (focussed beam) ALICE week / Offline meeting - March 15, 2004 5
Hit distributions D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 6
Cluster analysis (I) Ø Cluster definition: group of fired pixels sharing a common side D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 7
Cluster analysis (II) Ø Cluster size: number of fired pixels in the cluster D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 8
Cluster analysis (II) Ø Cluster size: number of fired pixels in the cluster Ø Cluster dimx, y: dimy x and y dimensions of a box containing the cluster: dimx D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 9
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 1 st minibus D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 11
Alignment procedure (II) Correlation plots for the 2 nd minibus D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 12
Alignment procedure (III) Correlation plots minibus planes aligned D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 13
Alignment procedure (IV) § Final step: alignment between the 2 minibus D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 14
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: s(x) = 110 mm s(y) = 21 mm D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 15
Resolution study (II) Selecting cluster size = 1 on middle plane: rms(x) = 127 mm s(y) = 21 mm Selecting cluster size = 2 on middle plane: s(x) = 42 mm s(y) = 20 mm D. Elia, R. Santoro 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 D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 17
- Slides: 16