Transcript ppt

SVAC
Instrument Analysis Meeting, August 29, 2005
Preparing for 8 Tower + ACD data
Eric Charles
for the SVAC group & friends
(Heather & Alex Moiseev mainly)
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Goals & Outline
• 8 Tower + ACD runs will be first chance to try integrating the
ACD into the LAT reconstruction & analysis chain
– We want to be able to run sensibly and quickly identify
any problems we encounter
• Peparing for running
– Intergration into LAT enviroment is ongoing
– Thresholds & pedestals have been defined by ACD group
– We need region of intrest mapping for 8 tower running
• Planning for analyzing the data
– Verifying that needed ACD digi information is available
– Adding information in reconstruction to study ACD
behavior
• Track extrapolation to the ACD
• To do list and status
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
ACD Tile Naming
Top tiles are
000-044
-x tiles are
100-130
-y tiles are
200-230
+x tiles are
300-330
+y tiles are
400-430
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Tile-tower coincidence rates
Side tiles and side towers
Goal: To generate RoIs (Regions
of Intrest = tiles) associated
with each tower
Top tiles
Eric Charles
We look at the correllations
between which ACD tiles fire
and which tower has the most
Tracker hits
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SVAC
Instrument Analysis Meeting, August 29, 2005
Setting the ROI mapping
MC: 200k Surface muons
One entry per tile-tower
pair (top) (side)
We cut at 250 coincidences
for 200k generated surface
muons.
All combinations above that
rate go into the ROI table
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
ROI map for 8-tower + ACD runs
Tower
roi0
roi1
roi4
roi5
roi8
roi9
roiC
roiD
=
=
=
=
=
=
=
=
Corresponding tile names
000,001,010,011,100,101,110,111,200,201,210,211
000,001,002,003,010,011,012,013,201,202,211,212
000,010,011,020,201,101,102,111,112
001,010,011,012,013,020,021,022,023
020,021,030,031,040,102,103,112,113
020,021,022,023,030,031,032,033,041
030,031,040,041,103,104,113,114,400,401,410,411
030,031,032,033,040,041,042,043,401,402,411,412
Tiles-Tower pairs in red do not show up in the default flight configuration
Just under half (8/20) of the new pairs involve tiles above the missing towers.
This is expected as those towers are not present & so can not be used in a coincidence.
The “other” half of the new pairs involve tiles that are not quite above the towers in
question. This is really a matter of how tightly or loosely we choose to define the
anti-coincidence veto.
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Validating ACD digi level data
Hits above Veto threshold
Hits above Low Discriminator
threshold
All Hits
Difference between last two
plots in when noise fires the
other discriminator
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Recon level ACD information
• The existing information at recon level is mainly geared
towards analysis
– Distance of Closest Approach (DOCA)
• Closest distance to center of any hit tile
– Measured normal to track (out of tile plane)
– Active distance
• Largest signed distance from edge of any hit tile
– Measured in plane of tile
– + is inside a hit tile, - is outside the hit tile
• We want to add information about where the track is expected
to intersect the ACD
– Testing the out in ROOT, will the port it to gaudi tools that
uses the full geometry
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Extrapolating tracks to ACD
• The Cartesian geometry of the LAT makes this very easy
• Sort of like driving around in the inner sunset
• Step1: determine which side (or top) of the LAT the track
entered from
– Calculate the length back along the track to the planes that
define each of the side of the ACD
– Take whichever side (or the top) has the first intersection
• Step2: back-project the track to the ACD intersection
– XACD = X0 – L V0
• Step3: work out which tile the intersection corresponds to
– To do this correctly requires full ACD geometry and use the
propagator
• Step4: caculate other useful information about the intersection
– Pathlength in plastic, projection of track errors....
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Information to Add to AcdRecon
Class TkrAcdIntersection {
AcdId
m_tileId;
Add one TkrAcdIntersection
object per track as diagnostic
tool
HepVector3D m_globalIntersection;
double
m_localX;
double
m_localY;
double
double
double
m_localXXCov;
m_localXYCov;
m_localYYCov;
double
double
m_trackLengthToIntersection;
m_pathlenghtInTile;
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Missing-Hit Maps
Only looking at top tiles
All Events
Here we see problems
with my geometry model
No hit in expected tile
No ACD hit
Here we see gaps in ACD
(ribbons are not included yet)
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Track Extrapolation Accuracy
We focus in on a region
near the 2mm tile gap
Almost all events with
no ACD hits have tracks
that extrapolate to very
close to this region
ACD hit
No ACD hit
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Pathlength Through Scintillator
We want to be
Black (red) curves
are for top (side)
tiles
able to correct
the signal size in
the ACD for the
pathlength of the
track
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Work to Do
• Move test software into release
– Adding TkrAcdIntersection to TDS
– Move intersection calculation code to a gaudi tool
– Add relevent information to documentation
• Add ACD information to SVAC ntuple
• Define set of performance quantities that we want offline
– Inefficiency maps
– Pulse-Height tomography studies
• Add ACD related information to SVAC reports
– Digi level report
• Pulse height and trigger information
– Recon level report
• Expected intersection and missing hit-maps information
Eric Charles
1
SVAC
Instrument Analysis Meeting, August 29, 2005
Summary
• We are ready to do basic checks on the ACD data quality and
offline calibrations
– Using muons to calibrated veto thresholds offline
• We are getting tools in place to be able to slightly more
sophisticated offline analysis
– Doing studies that use the track extrapolation to the ACD
Eric Charles
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