SiLinearChargeDivider Class Reference

#include <SiLinearChargeDivider.h>

Inheritance diagram for SiLinearChargeDivider:

Public Member Functions
SiChargeDivider::ionization_type	divide (const PSimHit *, const LocalVector &, double, const StripGeomDetUnit &det, CLHEP::HepRandomEngine *)
void	setParticleDataTable (const ParticleDataTable *pdt)
	SiLinearChargeDivider (const edm::ParameterSet &conf)
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 (double const particleMass, float momentum, float eloss, float length, int NumberOfSegmentation, float elossVector[], CLHEP::HepRandomEngine *)
float	PeakShape (const PSimHit *, const StripGeomDetUnit &det)
float	TimeResponse (const PSimHit *hit, const StripGeomDetUnit &det)

Private Attributes
const int	chargedivisionsPerStrip
const double	cosmicShift
const double	deltaCut
std::unique_ptr < SiG4UniversalFluctuation >	fluctuate
const bool	fluctuateCharge
const bool	peakMode
const ParticleDataTable *	theParticleDataTable

Static Private Attributes
static float const	decoValues [651]
static float const	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 27 of file SiLinearChargeDivider.h.

Constructor & Destructor Documentation

SiLinearChargeDivider::SiLinearChargeDivider

(

const edm::ParameterSet &

conf

)

Definition at line 7 of file SiLinearChargeDivider.cc.

                                                                        :
  // 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")),
  theParticleDataTable(0),
  // Geant4 engine used to fluctuate the charge from segment to segment
  fluctuate(new SiG4UniversalFluctuation()) {
}

SiLinearChargeDivider::~SiLinearChargeDivider ( )

virtual

Definition at line 26 of file SiLinearChargeDivider.cc.

                                             {
}

Member Function Documentation

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

private

Definition at line 135 of file SiLinearChargeDivider.cc.

References cosmicShift, decoValues, PSimHit::energyLoss(), PSimHit::localPosition(), mag(), GeomDet::surface(), PSimHit::tof(), Surface::toGlobal(), and 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, CLHEP::HepRandomEngine *  engine  )

virtual

Implements SiChargeDivider.

Definition at line 30 of file SiLinearChargeDivider.cc.

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

Referenced by cuy.FindIssue::__init__().

                                                                                                                                                                {

  // signal after pulse shape correction
  float const decSignal = TimeResponse(hit, det);

  // if out of time go home!
  if (0==decSignal) return ionization_type();

  // 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( hit->particleType() );
  double const particleMass = particle ? particle->mass()*1000 : 139.57;
  double const particleCharge = particle ? particle->charge() : 1.;

  if(!particle) {
    LogDebug("SiLinearChargeDivider") << "Cannot find particle of type "<< hit->particleType() 
                                      << " in the PDT we assign to this particle the mass and charge of the Pion";
  }

  int NumberOfSegmentation = 
  // if neutral: just one deposit....
    (fabs(particleMass)<1.e-6 || particleCharge==0) ? 1 :
    // computes the number of segments from number of segments per strip times number of strips.
    (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();


  // Prepare output
  ionization_type _ionization_points;
  _ionization_points.resize(NumberOfSegmentation);

  // Fluctuate charge in track subsegments
  LocalVector direction = hit->exitPoint() - hit->entryPoint();
  if (NumberOfSegmentation <=1) {
    // here I need a random... not 0.5
    _ionization_points[0] = EnergyDepositUnit(eLoss*decSignal/eLoss,
                          hit->entryPoint()+0.5f*direction);
  }else {
    float eLossVector[NumberOfSegmentation];
    if( fluctuateCharge ) {
      fluctuateEloss(particleMass, hit->pabs(), eLoss, direction.mag(), NumberOfSegmentation, eLossVector, engine);
      // 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);
      }
    }
  }
  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 ( double const  particleMass, float  momentum, float  eloss, float  length, int  NumberOfSegmentation, float  elossVector[], CLHEP::HepRandomEngine *  engine  )

private

Definition at line 95 of file SiLinearChargeDivider.cc.

References deltaCut, fluctuate, i, and cuy::ii.

Referenced by divide().

                                                                         {


  // 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, engine)/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 127 of file SiLinearChargeDivider.cc.

References cosmicShift, PSimHit::energyLoss(), PSimHit::localPosition(), mag(), peakValues, GeomDet::surface(), PSimHit::tof(), Surface::toGlobal(), and 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 40 of file SiLinearChargeDivider.h.

References theParticleDataTable.

{ theParticleDataTable = pdt; }

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));
  } 

Member Data Documentation

const int SiLinearChargeDivider::chargedivisionsPerStrip

private

Definition at line 46 of file SiLinearChargeDivider.h.

Referenced by divide().

const double SiLinearChargeDivider::cosmicShift

private

Definition at line 48 of file SiLinearChargeDivider.h.

Referenced by DeconvolutionShape(), and PeakShape().

float const SiLinearChargeDivider::decoValues

staticprivate

Definition at line 71 of file SiLinearChargeDivider.h.

Referenced by DeconvolutionShape().

const double SiLinearChargeDivider::deltaCut

private

Definition at line 47 of file SiLinearChargeDivider.h.

Referenced by fluctuateEloss().

std::unique_ptr<SiG4UniversalFluctuation> SiLinearChargeDivider::fluctuate

private

Definition at line 53 of file SiLinearChargeDivider.h.

Referenced by fluctuateEloss().

const bool SiLinearChargeDivider::fluctuateCharge

private

Definition at line 45 of file SiLinearChargeDivider.h.

Referenced by divide().

const bool SiLinearChargeDivider::peakMode

private

Definition at line 44 of file SiLinearChargeDivider.h.

Referenced by TimeResponse().

float const SiLinearChargeDivider::peakValues

staticprivate

Definition at line 69 of file SiLinearChargeDivider.h.

Referenced by PeakShape().

const ParticleDataTable* SiLinearChargeDivider::theParticleDataTable

private

Definition at line 50 of file SiLinearChargeDivider.h.

Referenced by divide(), and setParticleDataTable().