GGEMSPhotoElectricEffect.cc

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// * This file is part of GGEMS.                                          *
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#include "GGEMS/materials/GGEMSMaterials.hh"
#include "GGEMS/physics/GGEMSPhotoElectricEffect.hh"
#include "GGEMS/physics/GGEMSSandiaTable.hh"
 
 
GGEMSPhotoElectricEffect::GGEMSPhotoElectricEffect(std::string const& primary_particle, bool const& is_secondary)
: GGEMSEMProcess()
{
  GGcout("GGEMSPhotoElectricEffect", "GGEMSPhotoElectricEffect", 3) << "GGEMSPhotoElectricEffect creating..." << GGendl;
 
  process_name_ = "Photoelectric";
 
  // Check type of primary particle
  if (primary_particle != "gamma") {
    std::ostringstream oss(std::ostringstream::out);
    oss << "For PhotoElectric effect, incident particle has to be a 'gamma'";
    GGEMSMisc::ThrowException("GGEMSPhotoElectricEffect", "GGEMSPhotoElectricEffect", oss.str());
  }
 
  process_id_ = PHOTOELECTRIC_EFFECT;
  primary_particle_ = "gamma";
  secondary_particle_ = "e-";
  is_secondaries_ = is_secondary;
 
  GGcout("GGEMSPhotoElectricEffect", "GGEMSPhotoElectricEffect", 3) << "GGEMSPhotoElectricEffect created!!!" << GGendl;
}
 
 
GGEMSPhotoElectricEffect::~GGEMSPhotoElectricEffect(void)
{
  GGcout("GGEMSPhotoElectricEffect", "~GGEMSPhotoElectricEffect", 3) << "GGEMSPhotoElectricEffect erasing..." << GGendl;
 
  GGcout("GGEMSPhotoElectricEffect", "~GGEMSPhotoElectricEffect", 3) << "GGEMSPhotoElectricEffect erased!!!" << GGendl;
}
 
 
GGfloat GGEMSPhotoElectricEffect::ComputeCrossSectionPerAtom(GGfloat const& energy, GGuchar const& atomic_number) const
{
  // Threshold at 10 eV
  GGfloat e_min = std::fmax(GGEMSSandiaTable::kIonizationPotentials[atomic_number], 10.0f)*eV;
  if (energy < e_min) return 0.0f;
 
  GGint start = GGEMSSandiaTable::kCumulativeIntervals[atomic_number-1];
  GGint stop = start + GGEMSSandiaTable::kNumberOfIntervals[atomic_number];
 
  GGint pos = stop;
  while (energy < static_cast<GGfloat>(GGEMSSandiaTable::kSandiaTable[pos][0])*keV) --pos;
 
  GGfloat aover_avo = ATOMIC_MASS_UNIT * static_cast<GGfloat>(atomic_number) / GGEMSSandiaTable::kZtoARatio[atomic_number];
 
  GGfloat energy_inv = 1.0f / energy;
  GGfloat energy_inv2 = energy_inv * energy_inv;
 
  return static_cast<GGfloat>(
    energy_inv * GGEMSSandiaTable::kSandiaTable[pos][1] * aover_avo * 0.160217648e-22 +
    energy_inv2 * GGEMSSandiaTable::kSandiaTable[pos][2] * aover_avo * 0.160217648e-25 +
    energy_inv * energy_inv2 * GGEMSSandiaTable::kSandiaTable[pos][3] * aover_avo * 0.160217648e-28 +
    energy_inv2 * energy_inv2 * GGEMSSandiaTable::kSandiaTable[pos][4] * aover_avo * 0.160217648e-31);
}