OPERA brick (16215) scanning results Luisa Arrabito on behalf of Lyon Scanning Group Emulsion Workshop Nagoya 22th-23th January 2008

CC Event

SUMMARY Two Predictions from CS : 1) Muon X = 71339SX = Y = 18524SY = ) Other X = 68829SX = Y = 21576SY = Both tracks have been located in plate 57 CS-Brick Connection : 1) Muon DX = 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 2 broad peaks are visible They correspond to transport tracks No alignment peak at nominal distance (1300 µm) for up to 4 cm 2

Scanback performed using X ray lateral marks Muon Other Stop in plate 50 ID_PLATE PATH Ncand Fill Factor = 100% Only 1 candidate for prediction within 100 μm and 30 mrad Scanback parameters : Pos tol. = ( *slope) μm Angular tol. = *slope Max missing plates = 5 ->Track stops in plate 57 -> High ionizing particle -> This is confirmed also in CS

SB Angular residuals SB Position residuals σ ~2.4 mrad RMS ~ 28 µm

Total Scan : Angular residuals Position residuals Scan of a large area 8 cm cm 2 because of the low cosmics density x 5 plates upstream + 8 plates downstream σ ~7-8 mrad σ ~ 3 µm

Vertex confirmation Muon Vertex multiplicity 4 IDIP µm µm µm muon µm Pl 57 Total Scan efficiency ~80%

All tracks attached to the vertex were followed down Follow down parameters : Pos tol. = ( *slope) μm Angular tol. = *slope Max missing plates = 5 Fill Factor = 25/30 = 83% Only 1 candidate for prediction within 100 μm and 30 mrad Follow down Predictions sent to LNGS for confirmation in CS

Follow down angular residuals Follow down position residuals RMS ~ µm σ ~ 3-4 mrad

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