Full simulation study Full simulation study of the T2K TPCof the T2K TPC

Dean Karlen, U. Victoria & TRIUMFDean Karlen, U. Victoria & TRIUMF

ILC TPC Analysis JamboreeILC TPC Analysis Jamboree

February 14, 2006February 14, 2006

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Simulation programsSimulation programs Neutrino interactions are simulated by Neutrino interactions are simulated by

Neut, using the expected Neut, using the expected spectrum at spectrum at the off-axis detectorthe off-axis detector

GEANT3 propagates the particles through GEANT3 propagates the particles through a gas volume in a 0.2 T magnetic fielda gas volume in a 0.2 T magnetic field– energy loss in the gas is recorded in 1 mm energy loss in the gas is recorded in 1 mm

stepssteps jtpc program reads the energy loss info:jtpc program reads the energy loss info:

– generates electrons in the TPC gas and generates electrons in the TPC gas and transports electrons to endplate transports electrons to endplate

– simulates gas amplification simulates gas amplification – assigns electrons to pads, producing signalsassigns electrons to pads, producing signals– pre-amplifies, shapes, digitizes, writes to filespre-amplifies, shapes, digitizes, writes to files

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Simulation parametersSimulation parametersTPC parameters

electronics parameters

typical digitized signal

Ar CO2

(90:10)

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Simulation geometrySimulation geometry

60 cm

120

cm

60 cm

E, B

interactions occurat edge of TPC

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Reconstruction programReconstruction program jtpc package used analyze MC files:jtpc package used analyze MC files:

– reads digitized informationreads digitized information– reconstructs charge deposited on padsreconstructs charge deposited on pads– finds track (or uses MC cheat to “find finds track (or uses MC cheat to “find

track”)track”)– performs a track fit, by maximizing the performs a track fit, by maximizing the

likelihood of the observed pattern of likelihood of the observed pattern of charge sharing within the rows charge sharing within the rows to beam to beam directiondirection

– writes ntuple files – with truth and writes ntuple files – with truth and reconstructed informationreconstructed information

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Examples of delta ray Examples of delta ray eventsevents delta rays are included in simulationsdelta rays are included in simulations

– no special treatment in track fitno special treatment in track fit

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SummarySummary won’t bother showing results…won’t bother showing results…

The jtpc package includes a scheme The jtpc package includes a scheme for full simulation of TPC signalsfor full simulation of TPC signals

Resolutions from simulation and Resolutions from simulation and prototype data are very closeprototype data are very close– to see results, please refer to:to see results, please refer to:

NIMA 555 (2005) 80, physics/0509051NIMA 555 (2005) 80, physics/0509051