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OPERA brick (16215) scanning results. Luisa Arrabito on behalf of Lyon Scanning Group. Emulsion Workshop Nagoya 22th-23th January 2008. CC Event 186970035. SUMMARY. Two Predictions from CS : 1) Muon X = 71339 SX = -0.0418 Y = 18524 SY = 0.0903 2) Other X = 68829 SX = -0.2033
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OPERA brick (16215) scanning results Luisa Arrabito on behalf of Lyon Scanning Group Emulsion Workshop Nagoya 22th-23th January 2008
SUMMARY • Two Predictions from CS : • 1) Muon • X = 71339 SX = -0.0418 • Y = 18524 SY = 0.0903 • 2) Other • X = 68829 SX = -0.2033 • Y = 21576 SY = 0.0894 • Both tracks have been located in plate 57 • CS-Brick Connection : • 1) Muon • DX = -47.5 µm DSX = 4 mrad • DY = -6 µm DSY = 5 mrad • Grains = 25 • 2) Other • DX = -101 µm DSX = 14 mrad • DY = 35.3 µm DSY = 7 mrad • Grains = 27
The brick was exposed to cosmics vertically No alignment peak at nominal distance (1300 µm) for up to 4 cm2 2 broad peaks are visible They correspond to transport tracks
Other Muon Stop in plate 50 • Scanback performed using X ray lateral marks ->Track stops in plate 57 -> High ionizing particle -> This is confirmed also in CS Fill Factor = 100% Only 1 candidate for prediction within 100 μm and 30 mrad ID_PLATE PATH Ncand 53 1 1 57 2 1 54 1 1 52 1 1 57 1 1 50 1 1 51 1 1 55 1 1 56 1 1 Scanback parameters : Pos tol. = (100 + 10*slope) μm Angular tol. = 0.015 + 0.05*slope Max missing plates = 5
SB Angular residuals σ ~2.4 mrad SB Position residuals RMS ~ 28 µm
Total Scan : Scan of a large area 8 cm2 - 16 cm2 because of the low cosmics density x 5 plates upstream + 8 plates downstream Angular residuals σ ~7-8 mrad Position residuals σ ~ 3 µm
Vertex confirmation Pl 57 Muon Vertex multiplicity 4 ID IP 1 0.22 µm 2 5.04 µm 3 2.47 µm muon 4 5.42 µm Total Scan efficiency ~80%
Follow down All tracks attached to the vertex were followed down Fill Factor = 25/30 = 83% Only 1 candidate for prediction within 100 μm and 30 mrad Follow down parameters : Pos tol. = (100 + 10*slope) μm Angular tol. = 0.015 + 0.05*slope Max missing plates = 5 Predictions sent to LNGS for confirmation in CS
Follow down angular residuals σ ~ 3-4 mrad Follow down position residuals RMS ~ 22-29 µm
Conclusions : • The first CC event has been located in Lyon • Lateral X ray very promising for ScanBack • Some tests with a new dry objective and plate changer are going on • A new Total Scan is going on in order to have standard format for publication • Some more detailed analysis is going on (p measurement, …) • Data publication will come soon • A second OPERA brick will be in Lyon this week