#include <SiLinearChargeDivider.h>

Inheritance diagram for SiLinearChargeDivider:

Public Member Functions
SiChargeDivider::ionization_type	divide (const PSimHit *, const LocalVector &, double, const StripGeomDetUnit &det)

void	setParticleDataTable (const ParticleDataTable *pdt)

	SiLinearChargeDivider (const edm::ParameterSet &conf, CLHEP::HepRandomEngine &)

virtual	~SiLinearChargeDivider ()

Public Member Functions inherited from SiChargeDivider
virtual	~SiChargeDivider ()

Private Member Functions
float	DeconvolutionShape (const PSimHit *, const StripGeomDetUnit &det)

float	driftXPos (const Local3DPoint &pos, const LocalVector &drift, double thickness)

void	fluctuateEloss (int particleId, float momentum, float eloss, float length, int NumberOfSegmentation, float elossVector[])

float	PeakShape (const PSimHit *, const StripGeomDetUnit &det)

float	TimeResponse (const PSimHit *hit, const StripGeomDetUnit &det)

Private Attributes
int	chargedivisionsPerStrip

edm::ParameterSet	conf_

double	cosmicShift

double	deltaCut

SiG4UniversalFluctuation *	fluctuate

bool	fluctuateCharge

bool	peakMode

CLHEP::HepRandomEngine &	rndEngine

const ParticleDataTable *	theParticleDataTable

Static Private Attributes
static float	decoValues [651]

static float	peakValues [921]

Additional Inherited Members
Public Types inherited from SiChargeDivider
typedef std::vector < EnergyDepositUnit >	ionization_type

Detailed Description

Concrete implementation of SiChargeDivider. It divides the charge on the line connecting entry and exit point of the SimTrack in the Silicon. Effects that are considered here are:

fluctuations of the charge deposit fronm segment to segment
pulse shape ( in peak of deconvolution mode)

Definition at line 25 of file SiLinearChargeDivider.h.

Constructor & Destructor Documentation

SiLinearChargeDivider::SiLinearChargeDivider	(	const edm::ParameterSet &	conf,
		CLHEP::HepRandomEngine &	eng
	)

Definition at line 7 of file SiLinearChargeDivider.cc.

References chargedivisionsPerStrip, conf_, cosmicShift, deltaCut, fluctuate, fluctuateCharge, edm::ParameterSet::getParameter(), edm::ParameterSet::getUntrackedParameter(), peakMode, and rndEngine.

                                                                                                   :
   conf_(conf),theParticleDataTable(0),rndEngine(eng){
   // Run APV in peak instead of deconvolution mode, which degrades the time resolution.
   peakMode=conf_.getParameter<bool>("APVpeakmode");
 
   // Enable interstrip Landau fluctuations within a cluster.
   fluctuateCharge=conf_.getParameter<bool>("LandauFluctuations");
   
   // Number of segments per strip into which charge is divided during
   // simulation. If large, precision of simulation improves.
   chargedivisionsPerStrip=conf_.getParameter<int>("chargeDivisionsPerStrip");
  
   // delta cutoff in MeV, has to be same as in Geant (0.120425 MeV corresponding to 100um range for electrons)
   deltaCut=conf_.getParameter<double>("DeltaProductionCut");
 
   //Offset for digitization during the MTCC and in general for taking cosmic particle
   //The value to be used it must be evaluated and depend on the volume defnition used
   //for the cosimc generation (Considering only the tracker the value is 11 ns)
   cosmicShift=conf_.getUntrackedParameter<double>("CosmicDelayShift");
   
   // Geant4 engine used to fluctuate the charge from segment to segment
   fluctuate = new SiG4UniversalFluctuation(rndEngine);
 }

SiLinearChargeDivider::~SiLinearChargeDivider ( )

virtual

Definition at line 31 of file SiLinearChargeDivider.cc.

References fluctuate.

                                              {
   delete fluctuate;
 }

Member Function Documentation

float SiLinearChargeDivider::DeconvolutionShape	(	const PSimHit *	hit,
		const StripGeomDetUnit &	det
	)

private

Definition at line 127 of file SiLinearChargeDivider.cc.

References cosmicShift, decoValues, PSimHit::energyLoss(), PSimHit::localPosition(), mag(), GeomDet::surface(), PSimHit::tof(), Surface::toGlobal(), and vdt::x.

Referenced by TimeResponse().

                                                                                               {
   // x is difference between the tof and the tof for a photon (reference)
   // converted into a bin number
   int x = int(((det.surface().toGlobal(hit->localPosition()).mag()/30.) + cosmicShift - hit->tof())*10)+300;
   if(x < 0 || x > 650) return 0;
   return hit->energyLoss()*decoValues[x];
 }

SiChargeDivider::ionization_type SiLinearChargeDivider::divide	(	const PSimHit *	hit,
		const LocalVector &	driftdir,
		double	moduleThickness,
		const StripGeomDetUnit &	det
	)

virtual

Implements SiChargeDivider.

Definition at line 36 of file SiLinearChargeDivider.cc.

References chargedivisionsPerStrip, driftXPos(), PSimHit::energyLoss(), PSimHit::entryPoint(), PSimHit::exitPoint(), fluctuateCharge, fluctuateEloss(), i, StripTopology::localPitch(), PSimHit::localPosition(), PV3DBase< T, PVType, FrameType >::mag(), PSimHit::pabs(), PSimHit::particleType(), StripGeomDetUnit::specificTopology(), and TimeResponse().

                                                                                                                                   {
 
   // computes the number of segments from number of segments per strip times number of strips.
   int NumberOfSegmentation =  
     (int)(1 + chargedivisionsPerStrip*fabs(driftXPos(hit->exitPoint(), driftdir, moduleThickness)-
                                            driftXPos(hit->entryPoint(), driftdir, moduleThickness) )
                                      /det.specificTopology().localPitch(hit->localPosition())         ); 
  
   // Eloss in GeV
   float eLoss = hit->energyLoss();
 
   // signal after pulse shape correction
   float decSignal = TimeResponse(hit, det);
 
   // Prepare output
   ionization_type _ionization_points;
   _ionization_points.resize(NumberOfSegmentation);
 
   // Fluctuate charge in track subsegments
   LocalVector direction = hit->exitPoint() - hit->entryPoint();  
   float* eLossVector = new float[NumberOfSegmentation];
   if( fluctuateCharge ) {
     fluctuateEloss(hit->particleType(), hit->pabs(), eLoss, direction.mag(), NumberOfSegmentation, eLossVector);   
     // Save the energy of each segment
     for ( int i = 0; i != NumberOfSegmentation; i++) {
       // take energy value from vector eLossVector, 
       _ionization_points[i] = EnergyDepositUnit(eLossVector[i]*decSignal/eLoss,
                                                 hit->entryPoint()+float((i+0.5)/NumberOfSegmentation)*direction);
     }
   } else {
     // Save the energy of each segment
     for ( int i = 0; i != NumberOfSegmentation; i++) {
       // take energy value from eLoss average over n.segments.
       _ionization_points[i] = EnergyDepositUnit(decSignal/float(NumberOfSegmentation),
                                                 hit->entryPoint()+float((i+0.5)/NumberOfSegmentation)*direction);
     }
   }
  
   delete[] eLossVector;
   return _ionization_points;
 }

float SiLinearChargeDivider::driftXPos	(	const Local3DPoint &	pos,
		const LocalVector &	drift,
		double	thickness
	)

inlineprivate

Definition at line 55 of file SiLinearChargeDivider.h.

References PV3DBase< T, PVType, FrameType >::x(), and PV3DBase< T, PVType, FrameType >::z().

Referenced by divide().

                                                                                               { 
     return pos.x()+(thickness/2.-pos.z())*drift.x()/drift.z();
   }

void SiLinearChargeDivider::fluctuateEloss	(	int	particleId,
		float	momentum,
		float	eloss,
		float	length,
		int	NumberOfSegmentation,
		float	elossVector[]
	)

private

Definition at line 78 of file SiLinearChargeDivider.cc.

References deltaCut, alignCSCRings::e, fluctuate, i, LogDebug, SiG4UniversalFluctuation::SampleFluctuations(), and theParticleDataTable.

Referenced by divide().

                                                                                  {
 
   // Get the nass if the particle, in MeV.
   // Protect from particles with Mass = 0, assuming then the pion mass
   assert(theParticleDataTable != 0);
   ParticleData const * particle = theParticleDataTable->particle( pid );
   double particleMass = particle ? particle->mass()*1000 : 139.57;
   if(!particle) {
     LogDebug("SiLinearChargeDivider") << "Cannot find particle of type "<<pid
                                       << " in the PDT we assign to this particle the mass of the Pion";
   }
   if(fabs(particleMass)<1.e-6 || pid == 22) particleMass = 139.57;
 
   // Generate charge fluctuations.
   float sum=0.;
   double deltaCutoff;
   double mom = particleMomentum*1000.;
   double seglen = length/NumberOfSegs*10.;
   double segeloss = (1000.*eloss)/NumberOfSegs;
   for (int i=0;i<NumberOfSegs;i++) {
     // The G4 routine needs momentum in MeV, mass in MeV, delta-cut in MeV,
     // track segment length in mm, segment eloss in MeV 
     // Returns fluctuated eloss in MeV
     // the cutoff is sometimes redefined inside, so fix it.
     deltaCutoff = deltaCut;
     sum += (elossVector[i] = fluctuate->SampleFluctuations(mom,particleMass,deltaCutoff,seglen,segeloss)/1000.);
   }
   
   if(sum>0.) {  // If fluctuations give eloss>0.
     // Rescale to the same total eloss
     float ratio = eloss/sum;
     for (int ii=0;ii<NumberOfSegs;ii++) elossVector[ii]= ratio*elossVector[ii];
   } else {  // If fluctuations gives 0 eloss
     float averageEloss = eloss/NumberOfSegs;
     for (int ii=0;ii<NumberOfSegs;ii++) elossVector[ii]= averageEloss; 
   }
   return;
 }

float SiLinearChargeDivider::PeakShape	(	const PSimHit *	hit,
		const StripGeomDetUnit &	det
	)

private

Definition at line 119 of file SiLinearChargeDivider.cc.

References cosmicShift, PSimHit::energyLoss(), PSimHit::localPosition(), mag(), peakValues, GeomDet::surface(), PSimHit::tof(), Surface::toGlobal(), and vdt::x.

Referenced by TimeResponse().

                                                                                      {
   // x is difference between the tof and the tof for a photon (reference)
   // converted into a bin number
   int x = int(((det.surface().toGlobal(hit->localPosition()).mag()/30.) + cosmicShift - hit->tof())*2)+120;
   if(x < 0 || x > 920) return 0;
   return hit->energyLoss()*peakValues[x];
 }

void SiLinearChargeDivider::setParticleDataTable ( const ParticleDataTable * pdt )

inlinevirtual

Implements SiChargeDivider.

Definition at line 38 of file SiLinearChargeDivider.h.

References theParticleDataTable.

38 { theParticleDataTable = pdt; }

SiLinearChargeDivider::theParticleDataTable

const ParticleDataTable * theParticleDataTable

Definition: SiLinearChargeDivider.h:49

float SiLinearChargeDivider::TimeResponse	(	const PSimHit *	hit,
		const StripGeomDetUnit &	det
	)

inlineprivate

Definition at line 61 of file SiLinearChargeDivider.h.

References DeconvolutionShape(), peakMode, and PeakShape().

Referenced by divide().

                                                                               {
     return (peakMode ? PeakShape(hit,det) : DeconvolutionShape(hit,det));
   } 