TPC Detector Simulators

TPC Fast Simulator &TPC Response Simulator

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint Meeting

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint MeetingManuel Calderón de la Barca Sánchez

TPC Simulators

Simulate response of TPC Detector volume

Relevant processesIonization DriftAmplification in Sense WiresPad Plane Signal GenerationReadout Electronics

Rem. Sl. 8

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint MeetingManuel Calderón de la Barca Sánchez

Current Simulators

Fast Simulator : TFSFortran basedExtensively exercisedFast, but not very detailed

Slow Simulator : TRSC++ basedMore detailed breakdown of

interesting processesRem. Sl. 7

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint MeetingManuel Calderón de la Barca Sánchez

VERY Fast slide on TFS

Geant Hit Signal2 Widths: prf & z

Intrinsic Pad Response Drift Length Pad Crossing Angle Sense Wire Spacing Diffusion, Trans. & Lon. Electronics Shaping

Time & Sampling Frequency

Geant HitPositions Gaussian Smear = f(prf ) Hit Merging = f(prf , z )

TFS Output Tracking

Rem. Sl. 6

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint MeetingManuel Calderón de la Barca Sánchez

TRS: Factorization & OO

Is it possible to factorize the processes occurring in the chamber?

Study each process individuallyEach process a different base classAlgorithms for a particular process are

implemented in derived classes

Rem. Sl. 5

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint MeetingManuel Calderón de la Barca Sánchez

TRS : Processes

Charge TransportCharge CollectionAnalog Signal GenerationElectronics Response & Digitization

Rem. Sl. 4

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint MeetingManuel Calderón de la Barca Sánchez

Charge Transport

Transport charge (sub-)segments to sense wires. with field cage electrostatics ...Field Cage StructureE & B Field MapsWire Grid Transparency

… and Gas propertiesDrift velocityDiffusion & Absorption

Rem. Sl. 3

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint MeetingManuel Calderón de la Barca Sánchez

Analog Signal

Induced Charge on PadGas Gain

AmplificationGas Gain SaturationCross coupling

between adjacent rows

Noise generation

Implementations, e.g. induced charge:“Slow”

Image charge integral at the single electron level’

“Parameterized” Pad response

function

Rem. Sl. 2

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint MeetingManuel Calderón de la Barca Sánchez

Electronics Response

Amplification & GainAnalog shaping

response & time Gaussian, Asymmetric

Gaussian, convolution of shaper response funct. w/ longitudinally diffused cluster.

Sampling of signalDistribution of

charge into time bins

DigitizationAnalog to Digital

ConversionZero Suppression

Rem. Sl. 1

April 9, 2000 ALICE-STAR Joint MeetingALICE-STAR Joint MeetingManuel Calderón de la Barca Sánchez

Status & Summary

Algorithms being tested, debugged & refined (comparison w/ cosmic ray data)

Separation of Parameters & AlgorithmsDB Geometry, Gas, Calibration parametersCoordinate Transformations

Placed DB Utilities area for general use

Speed up Algorithms (~20 min/Central Hijing)

Rem. Sl. 0