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CS scanning @ LNGS

CS scanning @ LNGS. Current status and perspectives. CS scanning protocol. CSd are scanned according to fog level different cuts are applied for the two samples Double base-track search (STANDARD) Manual check validation Event validation In case of null (double bt) result: (MICRO)

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CS scanning @ LNGS

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  1. CS scanning @ LNGS Current status and perspectives

  2. CS scanning protocol • CSd are scanned according to fog level • different cuts are applied for the two samples • Double base-track search (STANDARD) • Manual check validation • Event validation • In case of null (double bt) result: (MICRO) • Compton alignment • ¾ search • In case of null result after ¾ search: • we rescan the event according to its topology • we expect to do it in 10% QE events (see Natalia’s talk) • request second brick and send the first back to detector (only after positive result of the second) • Support to the labs when the event is not located in ECC Automatic OPERA General Meeting in Ankara

  3. Current situation Currently using up to 7microscopes for the scanning+ 1 devoted to manual check 24/7 shift coverage was around 85% before Christmas, significantly reducedafterwards Scanning Station is able to digest 50÷60 CSd/week in this condition SySal2000 (VS6, ST8.5) Improvements excepted from the release made by Cristiano, tests foreseen OPERA General Meeting in Ankara

  4. 2008 run current numbers Updated up to March 31st, 2009 From July 2nd, 2008: we received 88 development batches @LNGS OPERA General Meeting in Ankara

  5. Analysis of the second extracted brick to evaluate the improvement in the location rate OPERA General Meeting in Ankara

  6. Preliminary results • These estimations are VERY PRELIMINARY for the following reasons: • some manual check not yet concluded • some event validation not yet concluded • 3/4 search not yet applied in case of null double base-track result • So the value has to be considered as a lower limit OPERA General Meeting in Ankara

  7. “No results” events OPERA General Meeting in Ankara

  8. CS scanning trend All CSd with fog<20 have been measured at least once, the analysis has been completed on a sample of events (see Natalia’s talk) New events are coming and the analysis on old events must be completed OPERA General Meeting in Ankara

  9. Black CS 1154 is black! OPERA General Meeting in Ankara

  10. High-fog CS scanning N (Fog > 10) = 114 (13.1 %) N (Fog > 20) = 51 (5.9 %) N (Fog > 30) = 21 (2.4 %) Current protocol: use ScanGrid when Fog > 10 grains/µm3 OPERA General Meeting in Ankara

  11. Estimates from the previous slide • The scanning rate is 50÷60 bricks/week, enough to follow the extraction/development rate  to be doubled for 2009 run (including second brick extraction) • The success rate ~ 60% has been slightly improved • ¾ routinely applied but still lengthy especially because of manual checks • rescanning OPERA General Meeting in Ankara

  12. Scanning speed Standard scanning ScanGrid cm2/h • Data from 7 microscopes, 2 microscopes are used with ScanGrid • For the low fog CS, the nominal speed is affected by the reduction of scanning thresholds • Scanning speed is strongly affected by fog level • ScanGrid will be extensively used. Increasing computing power is planned: an upgrade of the LNGS Scanning Station is on going OPERA General Meeting in Ankara

  13. CS scanning data quality notch OPERA General Meeting in Ankara

  14. CS track multiplicity OPERA General Meeting in Ankara

  15. CSd-TT comparison: NC events Nearest CS track with respect to the centroid of the electronic prediction Accuracy ~ 1 cm in both projections OPERA General Meeting in Ankara

  16. Scanning area per event NC CC OPERA General Meeting in Ankara

  17. Fading effect in CSd OPERA General Meeting in Ankara

  18. Fading effect in CSd 0<Days<30 30<Days<60 60<Days<90 Days>90 OPERA General Meeting in Ankara

  19. Estimation of veto track contamination • Tracks crossing CS are provided from Russian reconstruction, MORE statistics is NOW available • All tracks crossing the CSd scanned @ LNGS have been compared with the scanned and validated tracks in CSd (2600) • One-to-one pairs has been made using a 2 constructed using the tolerances of the reconstructed muons OPERA General Meeting in Ankara

  20. Tolerances used in the 2 definition ~ 7 mm ~ 8 mm ~ 17 mrad ~ 16 mrad OPERA General Meeting in Ankara

  21. Veto track selection 420 scanned tracks belong to a different event (90% C.L) Lower limit on candidate contamination: 420/2600 = ~ 15% OPERA General Meeting in Ankara

  22. Some rock muons Track 16 is our muon candidate for the event (2 = 0.89) Track 2 (2 = 0.17) and 10 (2 = 0.61) are likely two rock muons OPERA General Meeting in Ankara

  23. Brick developed with a veto track Track 6 (our muon candidate!) with 2 = 0.38 is like to be a veto track OPERA General Meeting in Ankara

  24. Improvements and conclusions • Shift coverage 24/7 (+15%) • Increase number (+3 from Lyon) of microscope (+43%) • Increase scanning speed (+13%) • Total rate increase: + 85% • Data quality improvements on going • Test new SySal2000, released by Cristiano • Procedure improvements • Compton alignment and ¾ search • Reduce the number of manual checks by using dedicated data taking (more frames, image analysis,…) under study • Minimize the contamination of cosmic ray and rock muon tracks to improve the purity of the selection OPERA General Meeting in Ankara

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