evgen::ldm::ReThrowRayTraceBox Class Reference

ReThrowRayTraceBox class definiton. More...

Inheritance diagram for evgen::ldm::ReThrowRayTraceBox:

Public Member Functions
	ReThrowRayTraceBox (fhicl::ParameterSet const &pset)
	Constructor. More...
	~ReThrowRayTraceBox ()
	Destructor. More...
void	configure (const fhicl::ParameterSet &) override
	Interface for configuring the particular algorithm tool. More...
bool	IntersectDetector (MeVPrtlFlux &flux, std::array< TVector3, 2 > &intersection, double &weight) override
TLorentzVector	ThrowMeVPrtlMomentum (const MeVPrtlFlux &flux)
double	MaxWeight () override
Public Member Functions inherited from evgen::ldm::IRayTrace
virtual	~IRayTrace () noexcept=default
	Virtual Destructor. More...
Public Member Functions inherited from evgen::ldm::IMeVPrtlStage
virtual	~IMeVPrtlStage () noexcept
	Virtual Destructor. More...
	IMeVPrtlStage (const char *name)
TVector3	RandomUnitVector ()
double	GetRandom ()
const char *	Name ()

Private Member Functions
void	CalculateMaxWeight ()

Private Attributes
geo::BoxBoundedGeo	fBox
unsigned	fNThrows
double	fReferenceLabSolidAngle
double	fReferencePrtlMass
int	fReferenceScndPDG
double	fReferenceKaonEnergy
double	fMaxWeight

Additional Inherited Members
Protected Attributes inherited from evgen::ldm::IMeVPrtlStage
CLHEP::HepRandomEngine *	fEngine
const char *	fName

Detailed Description

ReThrowRayTraceBox class definiton.

Definition at line 39 of file ReThrowRayTraceBox_tool.cc.

Constructor & Destructor Documentation

evgen::ldm::ReThrowRayTraceBox::ReThrowRayTraceBox

(

fhicl::ParameterSet const &

pset

)

Constructor.

Definition at line 77 of file ReThrowRayTraceBox_tool.cc.

                                                                   :
  IMeVPrtlStage("ReThrowRayTraceBox") 
{
    this->configure(pset);
}

evgen::ldm::ReThrowRayTraceBox::~ReThrowRayTraceBox

(

)

Destructor.

Definition at line 85 of file ReThrowRayTraceBox_tool.cc.

{
}

Member Function Documentation

void evgen::ldm::ReThrowRayTraceBox::CalculateMaxWeight ( )

private

Definition at line 120 of file ReThrowRayTraceBox_tool.cc.

                                            {
  double secondary_mass = 0.;
  switch (fReferenceScndPDG) {
    case 11:
    case -11:
      secondary_mass = Constants::Instance().elec_mass;
      break;
    case 13:
    case -13:
      secondary_mass = Constants::Instance().muon_mass;
      break;
    case 211:
    case -211:
      secondary_mass = Constants::Instance().piplus_mass;
      break;
    default:
      std::cerr << "RETHROWRAYTACE -- bad secondary pdg: " << fReferenceScndPDG << std::endl;
      std::cout << "RETHROWRAYTACE -- bad secondary pdg: " << fReferenceScndPDG << std::endl;
      break;
  }

  double p = twobody_momentum(Constants::Instance().kplus_mass, secondary_mass, fReferencePrtlMass);
  double E = sqrt(p*p + fReferencePrtlMass*fReferencePrtlMass);

  double kgamma = fReferenceKaonEnergy / Constants::Instance().kplus_mass;
  double kbeta = sqrt(1 - 1. / (kgamma * kgamma));

  double scale = kgamma * kgamma * (p + kbeta*E) * (p + kbeta*E) / (p*p);

  fMaxWeight = scale * fReferenceLabSolidAngle;
}

void evgen::ldm::ReThrowRayTraceBox::configure ( const fhicl::ParameterSet &  )

overridevirtual

Interface for configuring the particular algorithm tool.

Parameters

ParameterSet

The input set of parameters for configuration

Implements evgen::ldm::IMeVPrtlStage.

Definition at line 90 of file ReThrowRayTraceBox_tool.cc.

{
  if (pset.has_key("Box")) {
    std::array<double, 6> box_config = pset.get<std::array<double, 6>>("Box");
    // xmin, xmax, ymin, ymax, zmin, zmax
    fBox = geo::BoxBoundedGeo(box_config[0], box_config[1], box_config[2], box_config[3], box_config[4], box_config[5]);
  }
  else {
    const geo::GeometryCore *geometry = lar::providerFrom<geo::Geometry>();
    fBox = geometry->DetectorEnclosureBox(pset.get<std::string>("Volume"));
  }

  fNThrows = pset.get<unsigned>("NThrows", 10000);

  std::cout << "Detector Box." << std::endl;
  std::cout << "X " << fBox.MinX() << " " << fBox.MaxX() << std::endl;
  std::cout << "Y " << fBox.MinY() << " " << fBox.MaxY() << std::endl;
  std::cout << "Z " << fBox.MinZ() << " " << fBox.MaxZ() << std::endl;

  fReferenceLabSolidAngle = pset.get<double>("ReferenceLabSolidAngle");
  fReferencePrtlMass = pset.get<double>("ReferencePrtlMass");
  fReferenceScndPDG = pset.get<int>("ReferenceScndPDG");
  fReferenceKaonEnergy = pset.get<double>("ReferenceKaonEnergy");

  CalculateMaxWeight();

  // TEST: compare results of this weight to calcENuWeight

}

bool evgen::ldm::ReThrowRayTraceBox::IntersectDetector ( MeVPrtlFlux &  flux, std::array< TVector3, 2 > &  intersection, double &  weight  )

overridevirtual

Implements evgen::ldm::IRayTrace.

Definition at line 171 of file ReThrowRayTraceBox_tool.cc.

                                                                                                                 {
  // try out the mevprtl direction a bunch of times
  std::vector<std::vector<TVector3>> allIntersections;
  std::vector<TLorentzVector> allHMom;

  for (unsigned i = 0; i <= fNThrows; i++) {
    TLorentzVector mevprtl_mom = ThrowMeVPrtlMomentum(flux);
    std::vector<TVector3> box_intersections = fBox.GetIntersections(flux.pos.Vect(), mevprtl_mom.Vect().Unit());

    // Does this ray intersect the box?
    if (box_intersections.size() != 2) {
      continue;
    }

    TVector3 A = box_intersections[0];

    // if the ray points the wrong way, it doesn't intersect
    if (mevprtl_mom.Vect().Unit().Dot((A - flux.pos.Vect()).Unit()) < 0.) {
      std::cout << "RAYTRACE: MeVPrtl points wrong way" << std::endl;
      std::cout << "Pos: " << flux.pos.X() << " " << flux.pos.Y() << " " << flux.pos.Z() << std::endl;
      std::cout << "A: " << A.X() << " " << A.Y() << " " << A.Z() << std::endl;
      std::cout << "P: " << mevprtl_mom.Vect().Unit().X() << " " << mevprtl_mom.Vect().Unit().Y() << " " << mevprtl_mom.Vect().Unit().Z() << std::endl;
      continue;
    }

    // if we're here, we have a valid ray
    allIntersections.push_back(box_intersections);
    allHMom.push_back(mevprtl_mom);
  }

  std::cout << "Prtl intersected (" << allIntersections.size() << " / " << fNThrows << ") times.\n";

  // did we get a hit?
  if (allIntersections.size() == 0) {
    return false;
  }

  unsigned ind = CLHEP::RandFlat::shootInt(fEngine, 0, allIntersections.size()-1); // inclusive?

  TLorentzVector mevprtl_mom = allHMom[ind];
  std::vector<TVector3> box_intersections = allIntersections[ind];

  TVector3 A = box_intersections[0];
  TVector3 B = box_intersections[1];

  // make sure that the flux start lies outside the detector
  if ((flux.pos.Vect() - A).Mag() < (A-B).Mag() && (flux.pos.Vect() - B).Mag() < (A-B).Mag()) {
    throw cet::exception("ReThrowRayTraceBox Exception", "Input mevprtl flux starts inside detector volume: "
        "MeVPrtl start At: (" + std::to_string(flux.pos.X()) + ", " + std::to_string(flux.pos.Y()) + ", " + std::to_string(flux.pos.Z()) + "). "
        "Intersection A At: " + std::to_string(A.X()) + ", " + std::to_string(A.Y()) + ", " + std::to_string(A.Z()) + "). "
        "Intersection B At: " + std::to_string(B.X()) + ", " + std::to_string(B.Y()) + ", " + std::to_string(B.Z()) + ").\n"
    );
  } 

  // set things
  weight = (double)allIntersections.size() / fNThrows;
  flux.mom = mevprtl_mom;
  // transform to beam-coord frame
  flux.mom_beamcoord = mevprtl_mom;
  flux.mom_beamcoord.Boost(-flux.kmom.BoostVector()); // Boost to kaon rest frame
  flux.mom_beamcoord.Boost(flux.kmom_beamcoord.BoostVector()); // And to beam coordinate frame
  // Two boosts make a rotation!

  // Set the secondary 4-momentum
  flux.sec = flux.kmom - flux.mom;
  flux.sec_beamcoord = flux.kmom_beamcoord - flux.mom_beamcoord;

  if ((flux.pos.Vect() - A).Mag() < (flux.pos.Vect() - B).Mag()) {
    intersection = {A, B}; // A is entry, B is exit
  }
  else {
    intersection = {B, A}; // reversed
  }

  std::cout << "Kaon 4P: " << flux.kmom.E() << " " << flux.kmom.Px() << " " << flux.kmom.Py() << " " << flux.kmom.Pz() << std::endl;
  std::cout << "Selected Prtl 4P: " << flux.mom.E() << " " << flux.mom.Px() << " " << flux.mom.Py() << " " << flux.mom.Pz() << std::endl;
  std::cout << "Selected Scdy 4P: " << flux.sec.E() << " " << flux.sec.Px() << " " << flux.sec.Py() << " " << flux.sec.Pz() << std::endl;

  return true;
}

double evgen::ldm::ReThrowRayTraceBox::MaxWeight ( )

inlineoverridevirtual

Implements evgen::ldm::IMeVPrtlStage.

Definition at line 59 of file ReThrowRayTraceBox_tool.cc.

                                { 
      return fMaxWeight;
    }

TLorentzVector evgen::ldm::ReThrowRayTraceBox::ThrowMeVPrtlMomentum

(

const MeVPrtlFlux &

flux

)

Definition at line 152 of file ReThrowRayTraceBox_tool.cc.

                                                                               {
  // pick a direction for the rest-frame
  TVector3 dir = RandomUnitVector();

  // make the mevprtl momentum this
  // 
  // Move the mevprtl momentum back to the kaon rest frame
  TLorentzVector mevprtl_mom = flux.mom;
  mevprtl_mom.Boost(-flux.kmom.BoostVector());

  mevprtl_mom = TLorentzVector(mevprtl_mom.P() * dir, mevprtl_mom.E());

  // boost back
  mevprtl_mom.Boost(flux.kmom.BoostVector());

  return mevprtl_mom;
  
}

Member Data Documentation

geo::BoxBoundedGeo evgen::ldm::ReThrowRayTraceBox::fBox

private

Definition at line 64 of file ReThrowRayTraceBox_tool.cc.

double evgen::ldm::ReThrowRayTraceBox::fMaxWeight

private

Definition at line 74 of file ReThrowRayTraceBox_tool.cc.

unsigned evgen::ldm::ReThrowRayTraceBox::fNThrows

private

Definition at line 65 of file ReThrowRayTraceBox_tool.cc.

double evgen::ldm::ReThrowRayTraceBox::fReferenceKaonEnergy

private

Definition at line 70 of file ReThrowRayTraceBox_tool.cc.

double evgen::ldm::ReThrowRayTraceBox::fReferenceLabSolidAngle

private

Definition at line 67 of file ReThrowRayTraceBox_tool.cc.

double evgen::ldm::ReThrowRayTraceBox::fReferencePrtlMass

private

Definition at line 68 of file ReThrowRayTraceBox_tool.cc.

int evgen::ldm::ReThrowRayTraceBox::fReferenceScndPDG

private

Definition at line 69 of file ReThrowRayTraceBox_tool.cc.

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

• ReThrowRayTraceBox_tool.cc