RPC Alignment & Calibration Alignment & Calibration

RPC
Alignment & & Calibration
Calibration
Camilo Carrillo
on on behalf of of RPC team
CERN
Departamento de Física
UNIVERSIDAD DE LOS ANDES
Bogotá, Colombia

Outline
• DT Segment Extrapolation.
• Residuals Residuals.
• Residual distribution.
• Chambers with shifted residuals.
• CConclusions. l i
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Event display
RPC Digis + DT Segments
RRun 66722
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DT DT Segment Segment Extrapolation
Extrapolation is done along
a straight line segment by
segment.
Z
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Y
X

Y Residual
Residuals
Y
We use residuals to check
the quality q y of the tool used to
measure RPC efficiency with
segment extrapolation.
RPC
RPC Rec Hit
DT/
CSC
X
Point
extrapolated
from DT
Segment g
RResidual id l
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X

Residual Distribution
Distribution.
Residuals for all RPC system in the barrel.
h http://webcms.ba.infn.it/~webrpc/efficiency/66722,66740/indexWm2near.html
// b b i f i / b / ffi i /66722 66740/i d W 2 h l
We expect a gaussian
(mean ~ 0)
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CRAFT analysis shows
chambers with shifted
residuals.
However However...
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Chambers with shifts shifts > > 1cm
1cm
• Wheel -2
• RB2out S02 S02_M M -1 -1.03 03 • RB2out S05 S05_F F 11.087 087
• RB2out S02_B -1.075
• RB1out S08_B 1.043
• Wheel -1
• RB3- S06_B -1.013
• RB3+ S06_B -1.149
• RB3+ S06_F -1.192
• Wheel 0
• RB1in S02_F -1.054
• RB2in S02_B 2.659
• RB2in S02_M 2.781
• RB2in S02_F 2.742
• RB2i RB2in S0 S05_F F -1.095
109
• RB3- S02_B -1.083
• Wheel +1
• RB1out S06_B -1.281
• RB1out S06_F -1.001
• RB2out S06_F -1.017
• Wheel +2
• RB2in S01 S01_B B 33.991 991
• RB2in S01_F 3.895
• RB2in S02_F -1.018
• RB2out S02_B 1.132
• RB3- S02_B -1.07
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Possible explanations
explanations
• A) We have an actual disalignment in the
hardware
• B) The DT segments (position/direction) are
corrected by a alignment constants but the
RPC RecHits are not.
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Work to be done
•Implement p this analysis y for the End Capp with CSC
segments.
•Useamoreprecise p tool for the residuals computation p
(we already have the tool with Track extrapolation).
• Compare these results with the new RPC reconstruction
tool (including re-clusterization).
• Include residuals in Y and Z (Local Coordinates)
Coordinates).
• Understand the relative disalignment between RPC and
DT for each chamber in 3D 3D.
• Include the RPC alignment in the CMSSW framework.
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Conclusions
• CRAFT analysis data showed an unexpected shift in
the residuals for some RPC chambers.
• Our hypothesis is that this is due to a dis alignment
w.r.t DT.
•This could be understood understood, performing RPC and DT
alignment studies.
Suggestions, Questions? Thanks!
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