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Recent results from SPD beam test D. Elia, R. Santoro INFN Bari ALICE Collaboration - SPD Group. Half stave. Pb-Target. Mini bus 1. beam. Middle plane. Mini bus 0. Table. MWPC. Scintillators. Quartz. Table: 150 cm. SPD beam test in 2003 (I).
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Recent results from SPD beam test D. Elia, R. Santoro INFN Bari ALICE Collaboration - SPD Group ALICE Offline Week - June 2004
Half stave Pb-Target Mini bus 1 beam Middle plane Mini bus 0 Table MWPC Scintillators Quartz Table: 150 cm SPD beam test in 2003 (I) • 158 A GeV/c In beam (104 ions/spill, 15 days) 4 mm thick Pb target • 3 days with 120 GeV/c proton/pion beam ALICE Offline Week - June 2004
SPD beam test in 2003 (II) • Target: 4 mm Pb • Trigger: quartz counter (beam) + 2 cm x 2 cm scintillator (interactions) • Mini bus 0, 1: 2 single chips/mini bus mounted in crossed way • Middle plane: single chip under study • Half-stave: read out through MCM including optical module • 2.8 GB of data collected Half-stave Middle plane Mini bus 0 Mini bus 1 Target ALICE Offline Week - June 2004
SPD beam test in 2003 (III) • Used for this analysis: proton/pion beam data (detailed understanding of detector behaviour) ALICE Offline Week - June 2004
256 rows 425 mm 50 mm 32 columns SPD beam test in 2003 (III) Minibus 1 Test chip Minibus 0 • Main studies: - alignments, residuals and resolution - clusteranalysis - detection efficiency ALICE Offline Week - June 2004
SPD beam test in 2003 (III) Minibus 1 Test chip Minibus 0 • Available samples: - focussed and wide beam data - full scan of threshold settings - tilt angle scan (inclined tracks) ALICE Offline Week - June 2004
All cluster tupes: rms(x) = 117 mm s(y) = 14.9 mm Alignments • Alignment of the minibuses and track reconstruction • Fine tuning of the alignment for the test plane: • - track prediction residuals centering ALICE Offline Week - June 2004
Single pixel-clusters: rms(x) = 121 mm s(y) = 14.9 mm Double-pixel clusters: s(x) = 12.6 mm s(y) = 13.6 mm Residuals and resolution (I) ALICE Offline Week - June 2004
Residuals and resolution (II) Residuals for single pixel clusters: rms(x) = 121 mm s(y) = 14.9 mm @ VTH = 200 Spatial precision of the telescope (simulation): stelescope 10 mm spixel(x) = 121 mmspixel(y) = 11 mm ALICE Offline Week - June 2004
Impacts vs cluster size Single-pixel cluster Double-x-pixel cluster Double-y-pixel cluster ALICE Offline Week - June 2004
Double-x-pixel cluster X-impacts vs cluster size Single-pixel cluster @ VTH = 200 ALICE Offline Week - June 2004
X-impacts vs cluster size s = 15 mm @ VTH = 200 ALICE Offline Week - June 2004
Y-impacts vs cluster size Single-pixel cluster Double-y-pixel cluster ALICE Offline Week - June 2004
@ VTH=214 s(y) = 13.8 mm @ VTH=200 s(y) = 14.9 mm @ VTH=120 s(y) = 17.9 mm @ VTH=80 s(y) = 16.6 mm Residuals vs threshold (I) Single-pixel clusters ALICE Offline Week - June 2004
@ VTH=214 s(y) = 15.8 mm @ VTH=200 s(y) = 13.6 mm @ VTH=120 s(y) = 14.1 mm @ VTH=80 s(y) = 21.0 mm Residuals vs threshold (II) Double-y-pixel clusters ALICE Offline Week - June 2004
1 2 3 4 5 6 7 9 10 8 12 11 13 Cluster type studies (I) Following classification implemented: 14 = all other types ALICE Offline Week - June 2004
1 2 3 4 5 7 8 Cluster type studies (II) VTH = 200 ALICE Offline Week - June 2004
1 2 3 4 5 7 9 10 8 Cluster type studies (III) ALICE Offline Week - June 2004
6 12 11 13 Cluster type studies (III) ALICE Offline Week - June 2004
Cluster type studies (IV) VTH=214 VTH=200 ALICE Offline Week - June 2004
1 2 3 4 5 7 8 Cluster type studies (V) VTH = 214 ALICE Offline Week - June 2004
Cluster type studies (VI) VTH=200 VTH=180 ALICE Offline Week - June 2004
Cluster type studies (VII) VTH=140 VTH=120 ALICE Offline Week - June 2004
Cluster size vs threshold (I) @ VTH=214 @ VTH=200 @ VTH=160 @ VTH=90 ALICE Offline Week - June 2004
Cluster size vs threshold (II) ALICE Offline Week - June 2004
Threshold scan study: Efficiency study • Event selection: • - 1 cluster on each of the tracking planes • - track crossing the test plane (acceptance limits) • @ VTH>150: • - efficiency 99.9% ALICE Offline Week - June 2004