MaterialProperties.cxx

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/*
  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
*/

// MaterialProperties.cxx, (c) ATLAS Detector software
 
#include "TrkGeometry/MaterialProperties.h"
 
#include <iostream>
 
Trk::MaterialProperties::MaterialProperties(float path, float Xo, float Lo,
                                            float averageA, float averageZ,
                                            float averageRho, float dEdX)
    : m_material(Xo, Lo, averageA, averageZ, averageRho, dEdX),
      m_dInX0(Xo * Xo > 10e-10 ? path / Xo : 0.),
      m_dInL0(Lo * Lo > 10e-10 ? path / Lo : 0.),
      m_zOaTrTd(averageA * averageA > 10e-10
                    ? averageZ / averageA * averageRho * path
                    : 0.) {}
 
// TODO add constructor with element composition
Trk::MaterialProperties::MaterialProperties(const Trk::Material& material,
                                            float path)
    : m_material(material),
      m_dInX0(material.X0 * material.X0 > 10e-10 ? path / material.X0 : 0.),
      m_dInL0(material.L0 * material.L0 > 10e-10 ? path / material.L0 : 0.),
      m_zOaTrTd(material.A * material.A > 10e-10
                    ? path * material.Z / material.A * material.rho
                    : 0.) {}
 
Trk::MaterialProperties* Trk::MaterialProperties::clone() const {
  return new Trk::MaterialProperties(*this);
}
 
Trk::MaterialProperties& Trk::MaterialProperties::operator*=(float scale) {
  // assuming rescaling of the material thickness
  m_dInX0 *= scale;
  m_dInL0 *= scale;
  m_zOaTrTd *= scale;
 
  return (*this);
}
 
void Trk::MaterialProperties::addMaterial(const Trk::Material& mat,
                                          float dInX0) {
  // averaging factors based on thickness
  float fnew = dInX0 * mat.X0 / (m_dInX0 * m_material.X0 + dInX0 * mat.X0);
  float fold = 1. - fnew;
 
  // updated material thickness
  m_dInX0 += dInX0;
 
  // updated material
  m_material = Trk::Material(1. / (fnew / mat.X0 + fold / m_material.X0),
                             1. / (fnew / mat.L0 + fold / m_material.L0),
                             fnew * mat.A + fold * m_material.A,
                             fnew * mat.Z + fold * m_material.Z,
                             fnew * mat.rho + fold * m_material.rho);
 
  // updated derived members
  m_dInL0 = m_dInX0 * m_material.X0 / m_material.L0;
  m_zOaTrTd = m_material.A > 0 ? m_dInX0 * m_material.X0 * m_material.Z /
                                     m_material.A * m_material.rho
                               : 0;
}
 
void Trk::MaterialProperties::setMaterial(const Trk::Material& mat,
                                          float thickness) {
  // just overwrite what you have
  m_material = mat;
  m_dInX0 = thickness / mat.X0;
  m_dInL0 = thickness / mat.L0;
  m_zOaTrTd = mat.Z / mat.A * mat.rho * thickness;
}
 
void Trk::MaterialProperties::setDeDx(float dEdX) {
  // set the DE/DX value
  m_material.dEdX = dEdX;
}
 
MsgStream& Trk::operator<<(MsgStream& sl,
                           const Trk::MaterialProperties& mprop) {
  sl << "Trk::MaterialProperties: " << endmsg;
  sl << "   - thickness/X0                          = " << mprop.thicknessInX0()
     << endmsg;
  sl << "   - thickness                       [mm]  = " << mprop.thickness()
     << endmsg;
  sl << "   - radiation length X0             [mm]  = " << mprop.x0() << endmsg;
  sl << "   - nuclear interaction length L0   [mm]  = " << mprop.l0() << endmsg;
  sl << "   - average material Z/A*rho [gram/mm^3]  = "
     << mprop.zOverAtimesRho() << endmsg;
  return sl;
}
 
std::ostream& Trk::operator<<(std::ostream& sl,
                              const MaterialProperties& mprop) {
  sl << "Trk::MaterialProperties: " << std::endl;
  sl << "   - thickness/X0                          = " << mprop.thicknessInX0()
     << std::endl;
  sl << "   - thickness                       [mm]  = " << mprop.thickness()
     << std::endl;
  sl << "   - radiation length X0             [mm]  = " << mprop.x0()
     << std::endl;
  sl << "   - nuclear interaction length L0   [mm]  = " << mprop.l0()
     << std::endl;
  sl << "   - average material Z/A*rho [gram/mm^3]  = "
     << mprop.zOverAtimesRho() << std::endl;
  return sl;
}