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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.
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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 Graphic courtesy of Norman Graf, SLAC/Sandbox Studio
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
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
Helix Parameter Calculations • ω • δ xc= x + R sin f yc= y - R cosf δ = R - (xc2+ yc2)1/2 • Ф0 • tan λ tan λ =pz / (px2 + py2)1/2 • z0 z = z0 + s tanl
Pull Distributions • Error is different per fitted helix (track) • Tracks will go through different part of the detector • Multiple scattering • How many hits
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
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
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.
Future Work • As the detector evolves, different designs can be tested • Different and more complicated events can be run
Acknowledgements • Advisor: Richard Partridge • life saving help: CosminDeaconu • Everyone at SLAC • DOE
References J. Alcaraz, Helicoidal tracks. L3 Internal Note 1666, February 18, 1995. Internation Linear Collider website. http://www.linearcollider.org/cms/