OPERA brick scanning by the European Scanning System

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OPERA brick scanning by the European Scanning
System
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Basic concepts
DB is used as the backbone for operationsNot
only book-keeping but living memory and working
toolData immediately ready for publication
Scanback-scanforth-followdown proceduresCan use
base-tracks and/or microtracks
TotalScan can use volumes of any shapeContinuous
data quality monitoring20 cm2/h/side/stage
Optical/X-ray marks1-zone/3-zone/no
intercalibration by tracks
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Scanback-scanforth-followdown
Candidates are propagated with last
position/slope(position only if microtracks -
tunable)
Candidate selection based on1) slope
agreement2) track quality tolerance cuts3)
combined slopeposition agreement
Forking (multiple candidates) supported but not
yet used (relevant only on first plate)
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Scanback-scanforth-followdown
Typical performances using local intercalibration
4 micron
2 mrad
Fill factor in the range 85100 (base tracks)
or 97100 (mtracks) Stopping point is reliable
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Scanback-scanforth-followdown
Coming soon
Plate skipping to speed up search
Switching from Optical to Lateral X-ray and
vice-versa(for plates with damaged grid or X-ray
marks)
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TotalScan (Volume scan)
Continuous data quality monitoring
Base track density is a good quality
estimatorHowever, all microtracks are saved to
the DB
Data are already aligned (within 20 mm) if
calibrated optical marks orlateral X-ray marks
are used
Full reprocessing is available using DB data, as
deeply as with raw data files
The logical association between a volume and the
stopping point is savedand documented in the DB
(no need to guess)
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Vertex confirmation with TotalScan data
At least two volume scan data sets available
1) Intercalibration data around scanback path
(46 mm linear size) Hard cuts to
improve purity for intercalibration Alignment
and vertex reconstruction available few
seconds after end of scanback SB (red)
Intercal data (rainbow) 2) Volume scanning
around confirmed stopping point (1 cm2 at
least) Record all microtracks, focus on
efficiency Usually needs 12 hours scanning
Complete emulsion reconstruction possible
with full dataset
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Data quality with TotalScan data
Track precision is 0.9 mm already in preliminary
reconstructions(vertex confirmation), inclusive
of scattering effects
Dy fit-measure (mm)
Fill factor of volume tracks using microtracks is
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(re-analysis is obviously possible) Follow-down
obtained for free in many cases
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Intercalibration details
Track maps used to intercalibrate brick plates
together
3 zone scheme
Overall alignment
88 mm2/zone
Y alignment residuals (mm)vs. X (mm), plate by
plate
plate
X (mm)
1 zone scheme
3 micron
Local alignmentfollowing track
66 mm2
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Intercalibration details
Fixed reference on single plate obtained by
Optical Marks or Lateral X-ray
Automatic intercalibration by Lateral X-ray marks
Working and used in several labs as an
alternative to speed up scanningThe ESS can
switch from each method to the other
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Efficiency improvement
Fill factor of base tracks higher in SB (91)
than in TS (84)
Working group investigating
First results efficiency related to number of
trials in scanning(tracks in overlapping areas
have higher probability of being taken)
Work going on, checks on optical effects coming
soon
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Efficiency/precision improvement
Working group developing Z-synchronized data
taking
Z
Camera
Improved Z determination should increase base
track precision and efficiency, possibly
microtrack efficiency and precision too
Prototype SW expected in next weeks
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Conclusions
European Scanning System is already producing
complete emulsiondata sets (vertex location
study)
Data quality good, physics reconstructions in
emulsion also attempted
Data already available in Central DB for analysis
and algorithm testing
System still evolving, efficiency/precision
improvements going on( more to be shown during
Emulsion Workshop)