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Silicon Detector Design Study Tracking Analysis Program for the International Linear Collider. Pelham Keahey Richard Partridge SULI 2008. International Linear Collider (ILC). Graphic courtesy of ILC / form one visual communication. SiD Detector Concept Design. - PowerPoint PPT Presentation
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Silicon Detector Design Study Tracking Analysis Program for the International Linear Collider
Pelham Keahey
Richard PartridgeSULI 2008
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International Linear Collider (ILC)
Graphic courtesy of ILC / form one visual communication
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SiD Detector Concept Design
Graphic courtesy of Norman Graf, SLAC/Sandbox Studio
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Analysis Program Objectives
• Develop a program(s) to:• Display and analyze pull distributions of five
helix parameters• Track purity and the fake track rate• Track finding Efficiency
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Helix Parameters
• ω - curvature of the track• δ -distance of closest approach (dca)• Ф0 -azimuthmal angle of the momentum at
the dca• tan λ -dz/ds, slope in the sz plane• z0 -z position at the dca
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Helix Parameter Calculations• ω
• δxc = x + R sin fyc = y - R cos f
δ = R - (xc2 + yc
2)1/2
• Ф0
• tan λ tan λ = pz / (px
2 + py2)1/2
• z0z = z0 + s tanl
)arctan(0c
c
yx
-=f
)sin(0003.1
==p
qBR
z
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Pull Distributions
rFittedErroValueSimulationeFittedValu )( -
•Error is different per fitted helix (track)• Tracks will go through different part of the detector• Multiple scattering• How many hits
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Z0 Pull Distribution
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Purity—FakeTrack Rate
• Purity is taking the hits used to create a track and determining how many of those hits are actually from the MCParticle’s path being fitted
• For the Z0 events the tracking program produced no fake tracks. Fake Tracks are defined as having a purity less than 0.5
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(1-Purity) vs Hits
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Efficiency
• Efficiency is calculated by taking the number of found tracks divided by the number of tracks that could have been found
• The simulation is currently setup to ignore certain particles
• Pt<1.1 GeV (particle that doesn’t enter the calorimeter)
• Also if z0 > 9 mm and a δ > 9 mm• 7 hits minimum
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Efficiency vs Theta
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Efficiency vs Pt
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Wire View One (Rho-z) event # 130
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Wire View Two (xy) event # 130
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Results
• Purity: Tracks can be expected to be pure around 96.4+-0.2% of the time, depending on event.
• In the Z0 we found no tracks below the 0.5 purity margin.
• Efficiency: During the same event 98.6±0.1% of the findable tracks were found.
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Future Work
• As the detector evolves, different designs can be tested
• Different and more complicated events can be run
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Acknowledgements
• Advisor: Richard Partridge• life saving help: Cosmin Deaconu• Everyone at SLAC• DOE
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ReferencesJ. Alcaraz, Helicoidal tracks. L3 Internal Note 1666, February 18, 1995.
Internation Linear Collider website. http://www.linearcollider.org/cms/