Bias the Photon-Nuclear process. More...

#include <PhotoNuclear.h>

Public Member Functions
	PhotoNuclear (std::string name, const framework::config::Parameters &p)
	Constructor.

void	StartRun () override
	Method called at the beginning of a run.

G4VBiasingOperation *	ProposeOccurenceBiasingOperation (const G4Track track, const G4BiasingProcessInterface callingProcess) override

std::string	getProcessToBias () const override
	return the process we want to bias

std::string	getParticleToBias () const override
	return the particle that we want to bias

std::string	getVolumeToBias () const override
	return the volume we want to bias within

void	RecordConfig (ldmx::RunHeader &h) const override
	record the configuration into the run header

Public Member Functions inherited from simcore::XsecBiasingOperator
	XsecBiasingOperator (std::string name, const framework::config::Parameters &parameters)
	Constructor.

	DECLARE_FACTORY_WITH_WAREHOUSE (XsecBiasingOperator, std::shared_ptr< XsecBiasingOperator >, std::string, const framework::config::Parameters &)
	The BiasingOperator factory.

virtual	~XsecBiasingOperator ()=default
	Destructor.

void	StartRun ()
	Method called at the beginning of a run.

Private Attributes
G4BOptnChangeCrossSection *	em_xsec_operation_ {nullptr}
	Cross-section biasing operation for conversion process.

double	pn_xsec_unbiased_ {0}
	Unbiased photonuclear xsec.

double	pn_xsec_biased_ {0}
	Biased photonuclear xsec.

std::string	volume_
	Volume we are going to bias within.

double	threshold_
	minimum kinetic energy [MeV] for a track to be biased

double	factor_
	factor to bias PN by

bool	down_bias_conv_
	Should we down-bias the gamma conversion process?

bool	only_children_of_primary_
	Should we restrict biasing to only children of primary?

Static Private Attributes
static const std::string	CONVERSION_PROCESS = "conv"
	Geant4 gamma conversion process name.

Additional Inherited Members
Protected Member Functions inherited from simcore::XsecBiasingOperator
G4VBiasingOperation *	BiasedXsec (double biased_xsec)
	Helper method for passing a biased interaction length to the Geant4 biasing framework.

bool	processIsBiased (std::string process)
	Check if the given processed is being biased.

G4VBiasingOperation *	ProposeFinalStateBiasingOperation (const G4Track , const G4BiasingProcessInterface )
	Do not propose any biasing on final states.

G4VBiasingOperation *	ProposeNonPhysicsBiasingOperation (const G4Track , const G4BiasingProcessInterface )
	Do not propose any non-physics biasing.

Protected Attributes inherited from simcore::XsecBiasingOperator
G4BOptnChangeCrossSection *	xsec_operation_ {nullptr}
	Cross-section biasing operation.

G4ProcessManager *	process_manager_ {nullptr}
	Process manager associated with the particle of interest.

framework::logging::logger	the_log_
	Enable logging.

Detailed Description

Bias the Photon-Nuclear process.

Definition at line 14 of file PhotoNuclear.h.

Constructor & Destructor Documentation

◆ PhotoNuclear()

simcore::biasoperators::PhotoNuclear::PhotoNuclear	(	std::string	name,
		const framework::config::Parameters &	p )

Constructor.

Definition at line 8 of file PhotoNuclear.cxx.

    : XsecBiasingOperator(name, p) {
  volume_ = p.get<std::string>("volume");
  threshold_ = p.get<double>("threshold");
  factor_ = p.get<double>("factor");
  down_bias_conv_ = p.get<bool>("down_bias_conv");
  only_children_of_primary_ = p.get<bool>("only_children_of_primary");
}

References down_bias_conv_, factor_, framework::config::Parameters::get(), only_children_of_primary_, threshold_, and volume_.

Member Function Documentation

◆ getParticleToBias()

std::string simcore::biasoperators::PhotoNuclear::getParticleToBias ( ) const

inlineoverridevirtual

return the particle that we want to bias

Implements simcore::XsecBiasingOperator.

Definition at line 34 of file PhotoNuclear.h.

34{ return "gamma"; }

◆ getProcessToBias()

std::string simcore::biasoperators::PhotoNuclear::getProcessToBias ( ) const

inlineoverridevirtual

return the process we want to bias

Implements simcore::XsecBiasingOperator.

Definition at line 31 of file PhotoNuclear.h.

31{ return "photonNuclear"; }

◆ getVolumeToBias()

std::string simcore::biasoperators::PhotoNuclear::getVolumeToBias ( ) const

inlineoverridevirtual

return the volume we want to bias within

Implements simcore::XsecBiasingOperator.

Definition at line 37 of file PhotoNuclear.h.

37{ return volume_; }

References volume_.

◆ ProposeOccurenceBiasingOperation()

G4VBiasingOperation * simcore::biasoperators::PhotoNuclear::ProposeOccurenceBiasingOperation	(	const G4Track *	track,
		const G4BiasingProcessInterface *	callingProcess )

overridevirtual

Returns: Method that returns the biasing operation that will be used to bias the occurence of photonuclear events.

Implements simcore::XsecBiasingOperator.

Definition at line 30 of file PhotoNuclear.cxx.

                                                                           {
  // if we want to only bias children of primary, leave if this track is NOT a
  // child of the primary
  if (only_children_of_primary_ and track->GetParentID() != 1) {
    return nullptr;
  }
 
  // is this track too low energy to be biased?
  if (track->GetKineticEnergy() < threshold_) {
    return nullptr;
  }
 
  std::string current_process =
      callingProcess->GetWrappedProcess()->GetProcessName();
 
  // If the current process is what want to bias
  if (current_process.compare(this->getProcessToBias()) == 0) {
    G4double interaction_length =
        callingProcess->GetWrappedProcess()->GetCurrentInteractionLength();
 
    pn_xsec_unbiased_ = 1. / interaction_length;
 
    pn_xsec_biased_ = pn_xsec_unbiased_ * factor_;
 
    return BiasedXsec(pn_xsec_biased_);
  }
 
  // If the current process is conversion and we want to bias down
  // make sure that the biased electromagnetic xsec never falls below the
  // normal (unbiased) photon-nuclear cross section
  // In that regime, the PN events generated would almost certainly be over
  // sampled.
  if ((current_process.compare(CONVERSION_PROCESS) == 0) and down_bias_conv_) {
    G4double interaction_length =
        callingProcess->GetWrappedProcess()->GetCurrentInteractionLength();
 
    double em_xsec_unbiased = 1. / interaction_length;
 
    double em_xsec_biased =
        std::max(em_xsec_unbiased + pn_xsec_unbiased_ - pn_xsec_biased_,
                 pn_xsec_unbiased_);
    static auto material_tungsten =
        simcore::g4user::ptrretrieval::getMaterial("G4_W");
    auto interaction_material = track->GetMaterial();
    if ((em_xsec_biased == pn_xsec_unbiased_) &&
        (interaction_material == material_tungsten)) {
      ldmx_log(warn) << "EM XS = PN unbiased XS! The biasing factor ("
                     << factor_ << ") is too large for particle with energy "
                     << track->GetKineticEnergy()
                     << " and material = " << interaction_material->GetName();
    }
 
    em_xsec_operation_->SetBiasedCrossSection(em_xsec_biased);
    em_xsec_operation_->Sample();
 
    return em_xsec_operation_;
  }
  return nullptr;
}

References simcore::XsecBiasingOperator::BiasedXsec(), CONVERSION_PROCESS, down_bias_conv_, em_xsec_operation_, factor_, only_children_of_primary_, pn_xsec_biased_, pn_xsec_unbiased_, and threshold_.

◆ RecordConfig()

void simcore::biasoperators::PhotoNuclear::RecordConfig ( ldmx::RunHeader & h ) const

inlineoverridevirtual

record the configuration into the run header

Implements simcore::XsecBiasingOperator.

Definition at line 40 of file PhotoNuclear.h.

                                                     {
    h.setStringParameter("BiasOperators::PhotoNuclear::Volume", volume_);
    h.setFloatParameter("BiasOperators::PhotoNuclear::Threshold", threshold_);
    h.setFloatParameter("BiasOperators::PhotoNuclear::Factor", factor_);
    h.setIntParameter("BiasOperators::PhotoNuclear::Bias Conv Down",
                      down_bias_conv_);
    h.setIntParameter("BiasOperators::PhotoNuclear::Only Children Of Primary",
                      only_children_of_primary_);
  }

References down_bias_conv_, factor_, only_children_of_primary_, ldmx::RunHeader::setFloatParameter(), ldmx::RunHeader::setIntParameter(), ldmx::RunHeader::setStringParameter(), threshold_, and volume_.

◆ StartRun()

void simcore::biasoperators::PhotoNuclear::StartRun ( )

override

Method called at the beginning of a run.

Definition at line 18 of file PhotoNuclear.cxx.

                            {
  XsecBiasingOperator::StartRun();
 
  if (processIsBiased(CONVERSION_PROCESS)) {
    em_xsec_operation_ = new G4BOptnChangeCrossSection("changeXsec-conv");
  } else if (down_bias_conv_) {
    EXCEPTION_RAISE(
        "PhotoNuclearBiasing",
        "Gamma Conversion process '" + CONVERSION_PROCESS + "' is not biased!");
  }
}

References CONVERSION_PROCESS, down_bias_conv_, em_xsec_operation_, simcore::XsecBiasingOperator::processIsBiased(), and simcore::XsecBiasingOperator::StartRun().

Member Data Documentation

◆ CONVERSION_PROCESS

const std::string simcore::biasoperators::PhotoNuclear::CONVERSION_PROCESS = "conv"

staticprivate

Geant4 gamma conversion process name.

Definition at line 52 of file PhotoNuclear.h.

Referenced by ProposeOccurenceBiasingOperation(), and StartRun().

◆ down_bias_conv_

bool simcore::biasoperators::PhotoNuclear::down_bias_conv_

private

Should we down-bias the gamma conversion process?

Definition at line 73 of file PhotoNuclear.h.

Referenced by PhotoNuclear(), ProposeOccurenceBiasingOperation(), RecordConfig(), and StartRun().

◆ em_xsec_operation_

G4BOptnChangeCrossSection* simcore::biasoperators::PhotoNuclear::em_xsec_operation_ {nullptr}

private

Cross-section biasing operation for conversion process.

Definition at line 55 of file PhotoNuclear.h.

55{nullptr};

Referenced by ProposeOccurenceBiasingOperation(), and StartRun().

◆ factor_

double simcore::biasoperators::PhotoNuclear::factor_

private

factor to bias PN by

Definition at line 70 of file PhotoNuclear.h.

Referenced by PhotoNuclear(), ProposeOccurenceBiasingOperation(), and RecordConfig().

◆ only_children_of_primary_

bool simcore::biasoperators::PhotoNuclear::only_children_of_primary_

private

Should we restrict biasing to only children of primary?

Definition at line 76 of file PhotoNuclear.h.

Referenced by PhotoNuclear(), ProposeOccurenceBiasingOperation(), and RecordConfig().

◆ pn_xsec_biased_

double simcore::biasoperators::PhotoNuclear::pn_xsec_biased_ {0}

private

Biased photonuclear xsec.

Definition at line 61 of file PhotoNuclear.h.

61{0};

Referenced by ProposeOccurenceBiasingOperation().

◆ pn_xsec_unbiased_

double simcore::biasoperators::PhotoNuclear::pn_xsec_unbiased_ {0}

private

Unbiased photonuclear xsec.

Definition at line 58 of file PhotoNuclear.h.

58{0};

Referenced by ProposeOccurenceBiasingOperation().

◆ threshold_

double simcore::biasoperators::PhotoNuclear::threshold_

private

minimum kinetic energy [MeV] for a track to be biased

Definition at line 67 of file PhotoNuclear.h.

Referenced by PhotoNuclear(), ProposeOccurenceBiasingOperation(), and RecordConfig().

◆ volume_

std::string simcore::biasoperators::PhotoNuclear::volume_

private

Volume we are going to bias within.

Definition at line 64 of file PhotoNuclear.h.

Referenced by getVolumeToBias(), PhotoNuclear(), and RecordConfig().

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

SimCore/include/SimCore/BiasOperators/PhotoNuclear.h
SimCore/src/SimCore/BiasOperators/PhotoNuclear.cxx

Public Member Functions

Private Attributes

Static Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ PhotoNuclear()

Member Function Documentation

◆ getParticleToBias()

◆ getProcessToBias()

◆ getVolumeToBias()

◆ ProposeOccurenceBiasingOperation()

◆ RecordConfig()

◆ StartRun()

Member Data Documentation

◆ CONVERSION_PROCESS

◆ down_bias_conv_

◆ em_xsec_operation_

◆ factor_

◆ only_children_of_primary_

◆ pn_xsec_biased_

◆ pn_xsec_unbiased_

◆ threshold_

◆ volume_