Results from the SPD test beam data analysis D. Elia, R. Santoro (Bari)
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Transcript of Results from the SPD test beam data analysis D. Elia, R. Santoro (Bari)
D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 1
Results from the SPDResults from the SPDtest beam data analysistest beam data analysis
D. Elia, R. Santoro (Bari)
Look at the proton/pion beam data:
test beam setup clustering analysis alignment resolution studies
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2003 Beam Test Setup (I)
SPD Testbeam Setup(In-beam)
Table
MWPCQuartz Scintillators
Mini bus 0
Pb-Target
Table: 150 cm
beamMini bus 1
Middle plane
Half stave
158 GeV/A In ion beam ≈ 104 ions/spill (15 days) Pb target 4mm thick120 GeV protons (3 days)
D. Elia, R. Santoro ALICE week / Offline meeting - March 15, 2004 3
Target: 4 mm PbTrigger: 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 directionMiddle plane: single chip under study Half-stave read out through MCM including optical module 2.8 GB of data collected
2003 Beam Test Setup (II)
Half-staveTarget Mini bus 0
Mini bus 1
Middle plane
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Proton data samples/setup
Data taken with 120 GeV/c proton/pion beam:
Setup
Focussed and wide beam data available
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Hit maps (focussed beam)
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Hit distributions
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Cluster analysis (I)
Cluster definition: group of fired pixels sharing a common side
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Cluster analysis (II)
Cluster size: number of fired pixels in the cluster
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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:
dimx
dim
y
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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 plotsfor the 1st minibus
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Alignment procedure (II)
Correlation plotsfor the 2nd minibus
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Alignment procedure (III)
Correlation plotsminibus planes aligned
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Alignment procedure (IV) Final step: alignment between the 2 minibus
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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:
(x) = 110 m(y) = 21 m
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Resolution study (II)Selecting cluster size = 1on middle plane:
rms(x) = 127 m(y) = 21 m
(x) = 42 m(y) = 20 m
Selecting cluster size = 2on middle plane:
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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