Digitizer for Simulated Hits in the Vertex Detector. More...

#include <VTXDigitizer.h>

Inheritance diagram for VTXDigitizer:

Public Member Functions
	VTXDigitizer (const VTXDigitizer &)=delete

VTXDigitizer &	operator= (const VTXDigitizer &)=delete

virtual Processor *	newProcessor ()

virtual void	init ()
	Initialisation member function.

virtual void	processRunHeader (LCRunHeader *run)
	Processing of run header.

virtual void	processEvent (LCEvent *evt)
	Processing of one event.

virtual void	check (LCEvent *evt)
	Produces check plots.

virtual void	end ()
	Termination member function.

Protected Member Functions
void	FindLocalPosition (SimTrackerHit hit, double localPosition, double *localDirection)
	Finds coordinates.

void	TransformToLab (double xLoc, double xLab)

void	ProduceIonisationPoints (SimTrackerHit *hit)

void	ProduceSignalPoints ()

void	ProduceHits (SimTrackerHitImplVec &simTrkVec)

void	TransformXYToCellID (double x, double y, int &ix, int &iy)

void	TransformCellIDToXY (int ix, int iy, double &x, double &y)

void	PoissonSmearer (SimTrackerHitImplVec &simTrkVec)

void	GainSmearer (SimTrackerHitImplVec &simTrkVec)

void	PrintInfo (SimTrackerHit simTrkHit, TrackerHitImpl recoHit)

TrackerHitImpl *	ReconstructTrackerHit (SimTrackerHitImplVec &simTrkVec)

void	TrackerHitToLab (TrackerHitImpl *recoHit)

void	PositionWithinCell (double x, double y, int &ix, int &iy, double &xCell, double &yCell)

void	generateBackground (LCCollectionVec *col)

Protected Attributes
std::string	_colName {}
	Input collection name.

std::string	_outputCollectionName {}

std::string	_colVTXRelation {}

int	_nRun {}
	Run number.

int	_nEvt {}
	Event number.

double	_tanLorentzAngle {}
	tangent of Lorentz angle

double	_cutOnDeltaRays {}
	cut in MeV on delta electrons used in simulation of charge for each ionisation point

double	_diffusionCoefficient {}
	Diffusion coefficient in mm for nominla layer thickness.

int	_numberOfLayers {}
	layer thickness More...

double	_pixelSizeX {}

double	_pixelSizeY {}

double	_electronsPerKeV {}

double	_segmentDepth {}

double	_currentTotalCharge {}

std::vector< int >	_laddersInLayer {}

std::vector< float >	_layerRadius {}

std::vector< float >	_layerThickness {}

std::vector< float >	_layerHalfThickness {}

std::vector< float >	_layerLadderLength {}

std::vector< float >	_layerLadderHalfWidth {}

std::vector< float >	_layerPhiOffset {}

std::vector< float >	_layerActiveSiOffset {}

std::vector< float >	_layerHalfPhi {}

std::vector< float >	_layerLadderGap {}

std::vector< float >	_bkgdHitsInLayer {}

std::vector< float >	_layerLadderWidth {}

int	_currentLayer {}

int	_currentModule {}

int	_generateBackground {}

double	_currentParticleMomentum {}

double	_currentParticleEnergy {}

double	_currentParticleMass {}

double	_currentPhi {}

double	_widthOfCluster {}

double	PI {}

double	TWOPI {}

double	PI2 {}

double	SCALING {}

int	_produceFullPattern {}

int	_numberOfSegments {}

int	_debug {}

int	_PoissonSmearing {}

int	_electronicEffects {}

int	_useMCPMomentum {}

int	_removeDrays {}

double	_threshold {}

double	_currentLocalPosition [3] {}

double	_currentEntryPoint [3] {}

double	_currentExitPoint [3] {}

double	_electronicNoise {}

double	_segmentLength {}

IonisationPointVec	_ionisationPoints {}

SignalPointVec	_signalPoints {}

MyG4UniversalFluctuationForSi *	_fluctuate {}

double	_xLayerReco {}

double	_yLayerReco {}

double	_zLayerReco {}

double	_xLayerSim {}

double	_yLayerSim {}

double	_zLayerSim {}

int	_iLayer {}

int	_nCoveredX {}

int	_nCoveredY {}

int	_nCells {}

int	_totEntries {}

double	_totMomentum {}

double	_momX {}

double	_momY {}

double	_momZ {}

double	_eDep {}

double	_amplX [20] {}

double	_amplY [20] {}

double	_amplC [100] {}

double	_ampl {}

double	_amplMax {}

double	_eSum {}

double	_energyLoss {}

double	_clusterWidthX {}

double	_clusterWidthY {}

double	_ampl33 {}

double	_ampl55 {}

double	_ampl77 {}

int	_ncell33 {}

int	_ncell55 {}

int	_ncell77 {}

int	_storeNtuple {}

double	_xLocalRecoCOG {}

double	_yLocalRecoCOG {}

double	_xLocalRecoEdge {}

double	_yLocalRecoEdge {}

double	_xLocalSim {}

double	_yLocalSim {}

std::vector< SimTrackerHitImplVec >	_hitsInLayer {}

Detailed Description

Digitizer for Simulated Hits in the Vertex Detector.

Digitization follows the procedure adopted in the CMS software package.
For each Simulated Tracker Hit the intersection points with
the inner and outer boundaries of sensitive Si layer are calculated.
Track segment within a layer is approximated with the line.
It is divided by n subsegments, where n can be specified by a user
via external Processor parameter. For each subsegment the charge
is simulated according to Landau distribution as expected for Silicon.
The charge transfer from the middle point of track subsegment (referred
hereafter to as ionisation point)
to the outer collection plane is performed taking
into account Lorentz effect in the magnetic field
It is assumed that on the collection plane the electron cloud from
each ionisation point is spread according to the Gaussian distribution
whose width is proportional to the square-root of the drift distance.
The charge on each fired pixel is then calculated as a sum of contributions
from n Gaussians. The VTX ladder is assumed to have matrix of rectangular pixels
(In the future I plan to implement possibility of variying pixel size with
the z coordinate).
The output of the processor is the collection of Reconstructed Tracker Hits.
Each reconstructed hit is assigned the position of the center-of-gravity of
the cluster of fired pixels. Lorentz effect is corrected for.

Input collections and prerequisites

Processor requires collection of simulated vertex tracker hits.
If such a collection with the user specified name does not exist
processor takes no action.

Output

Processor produces an output collection of the Tracker Hits. Collection has name "VTXTrackerHits".

Parameters

CollectionName	name of input SimTrackerHit collection (default parameter value : "vxd01_VXD", taken from Mokka)
TanLorentz	tangent of the Lorentz angle (default parameter value : 0.8)
CutOnDeltaRays	cut on the energy of delta-electrons (in MeV) (default parameter value : 0.03)
Diffusion	diffusion coefficient for the nominal active layer thickness (in mm) (default parameter value : 0.002)
LayerThickness	thickness of the active Silicon layer (in mm) (default parameter value : 0.03744)
PixelSizeX	pixel size along direction perpendicular to beam axis (in mm) (default value : 0.025)
PixelSizeY	pixel size along beam axis (in mm) (default value : 0.025)
ElectronsPerMeV	number of electrons produced per MeV of deposited energy (default parameter value : 270.3)
Threshold	threshold on charge deposited on one pixel (in electons) (default parameter value : 200.0)
LaddersInLayer	vector of integers, numbers of phi-ladders in each layer (default parameter values : 8, 8, 12, 16, 20; taken from Mokka database for VXD model vxd01)
LadderRadius	vector of doubles, radii of layers (in mm) (default parameter values : 15.301, 26.301, 38.301, 49.301, 60.301; taken from Mokka database for VXD model vxd01)
ActiveLadderOffset	vector of doubles, offset of active Si layer along phi-angle (in mm) for each layer (default parameter values : 1.455, 1.39866, 2.57163, 3.59295, 4.42245)
LadderHalfWidth	vector of doubles, half-width of the ladders in each layer (in mm) (default parameter values : 6.5, 11.0, 11.0, 11.0, 11.0; taken from Mokka database for VXD model vxd01)
LadderGaps	vector of doubles, gaps between two symmetric ladders (+/-z) in mm (default parameter values : 0.0, 0.04, 0.04, 0.04, 0.04; taken from Mokka database)
PhiOffset	vector of doubles, offset in phi angle for starting ladder in each layer (default parameter values : 0, 0, 0, 0, 0; taken from Mokka database for VXD model vxd01)
SegmentLength	segment length along track path which is used to subdivide track into segments (in mm). The number of track subsegments is calculated as int(TrackLengthWithinActiveLayer/SegmentLength)+1 (default parameter value : 0.005)
WidthOfCluster	defines width in Gaussian sigmas to perform charge integration for a given pixel (default parameter value : 3.0)
ElectronicEffects	flag to switch on gaussian smearing of signal (electronic noise) (default parameter value : 1)
ElectronicNoise	electronic noise in electrons (default parameter value : 100)
GenerateBackground	flag to switch on pseudo-generation of pair background hits Background hits are uniformly generated in cosQ and Phi (default parameter value : 0)
BackgroundHitsPerLayer	expected mean value of background hits accumulated in each layer over readout time. This number is calculated as Number of background hits per bunch crossing times number of bunch crossings over integration time. (default values : 34400 23900 9600 5500 3100 corresponding to 100 overlaid bunch crossings)
Debug	boolean variable, if set to 1, printout is activated (default parameter value : 0)

Author: A. Raspereza, MPI Munich

Member Data Documentation

int VTXDigitizer::_numberOfLayers {}

protected

layer thickness

layer half-thickness

The documentation for this class was generated from the following file:

VTXDigitizer.h

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Input collections and prerequisites

Output

Member Data Documentation