CS scanning @ LNGS

Current status and perspectivesLuigi Esposito (European CS Scanning Team)

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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CS scanning protocol1. CSd are scanned according to fog level

– different cuts are applied for the two samples

2. Double base-track search (STANDARD)3. Manual check validation4. Event validation

5. In case of null (double bt) result: (MICRO)– Compton alignment– ¾ search

6. 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)

7. request second brick and send the first back to detector (only after positive result of the second)

8. Support to the labs when the event is not located in ECC

Automatic

See Fabio’s talk

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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Current situation• Currently using up to 7

microscopes for the scanning + 1 devoted to manual check

• 24/7 shift– coverage was around 85%

before Christmas, significantly reduced afterwards

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

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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Present numbers of the 2008 run• The status as of 16-1-2009 22:00 LNGS time• From 02-07-2008, 72 development batches not uniformly distributed in time

CS_DEVELOPED 818

EVENTS 712

CS_MEASURED 709

BRICK_DEVELOPED * 417

BLACK_CS 25

BRICK_BACK 8

* Including some ¾ search

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Event classification417 bricks were developed after positive result from the CS

scanning:– STANDARD search: 402– MICRO search: 15

Relative ratio may change since the micro-track search is in progress

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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Black CS

1154 is black!

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High fog CS

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High-fog CS scanning

N (Fog > 10) = 104 (12.9 %)N (Fog > 20) = 44 (5.4 %)N (Fog > 30) = 18 (2.2 %)

Current protocol:use ScanGrid when Fog > 10 grains/µm3

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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CS scanning trend

3 weeks to complete the scanning of the 1st extracted CSd (140 remaining)2nd probable bricks being extracted (4 weeks for 200)

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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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% can be slightly improved ¾ routinely applied but still lengthy

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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Scanning speedStandard scanningScanGrid

• 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 planned in the coming weeks

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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Data quality: impact of the rescanning

Scanning data quality (micro-track per view, emulsion thickness, reconstructed base-tracks) is monitored with an “online” toolAppropriate actions are taken when DQ is not satisfactory, such as CSD rescan on small areasProgressive reduction of rescanning while keeping constant the effectiveness

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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CS scanning data quality

notch

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CS track multiplicity

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CSd-TT comparison: NC events

Nearest CS track with respect to the centroid of the electronic prediction

Accuracy ~ 9 mm in both projections

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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Analysis of the second extracted brick to evaluate the improvement in the location

efficiencyEvents with a 2nd brick extracted 105

passing through track in 1st brick 11

1st brick still under analysis 19

1st brick developed 8

Both CS black 1

Not measured…yet 14

2nd CS scanned 52

2nd brick developed 20

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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Preliminary results

Measured Developed Ratio (%)1st brick 650 396 60.9 1.22nd brick 52 20 38.5 2.61st & 2nd brick 75.9

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

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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Complicated event #1

Two CSd measured: no convincing track to develop a brick

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Complicated event #2

First brick extracted

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Complicated event #2

Second brick extracted

20/01/2009 OPERA Collaboration Meeting in MIZUNAMI

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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– Test new SySal2000, released by Cristiano– Procedure improvements:– Compton alignment and ¾ search