Creation of a model where the muon flow forms ions in the volume of oxygen-nitrogen gas

Physics Processes, Models and Cross Sections
1

Faced two problems of the formation of ions of carbon isotopes in the volume of oxygen, nitrogen gas and an unexpectedly small number of secondary particles (ions) from muons. I will be very grateful for any help.

I am trying to create a model of the formation of ions from muons in the atmosphere.
I want to record all the ions that are formed in the volume and record their properties, I am primarily interested in their charge and element (I expect to receive oxygen and nitrogen ions).
Problems I encountered

  1. Unexpectedly small number of registered shares
  2. I fix the ions of carbon isotopes, namely C12, C13.

What should you pay attention to in order to build a physically correct model?

this is what my SteppingAction class looks like

#include "MySteppingAction.hh"
#include "G4SystemOfUnits.hh"
#include "G4Step.hh"
#include "G4Track.hh"
#include "G4ParticleDefinition.hh"
#include <fstream>
#include <string>

MySteppingAction::MySteppingAction() {}

MySteppingAction::~MySteppingAction() {}

void MySteppingAction::UserSteppingAction(const G4Step* step)
{
  G4Track* track = step->GetTrack();
  G4ParticleDefinition* particle = track->GetDefinition();

  if (track->GetParentID() == 0) {
    WriteGeneratedParticleToFile(track);
  }

  std::cout << "Checking particle: " << particle->GetParticleName() << "\n";

  if (particle->GetParticleType() == "nucleus" && particle->GetParticleSubType() == "generic") {
    std::cout << "Ion detected: " << particle->GetParticleName() << "\n";

    IonInfo ion;
    ion.stepNumber = step->GetTrack()->GetCurrentStepNumber();
    ion.trackID = track->GetTrackID();
    ion.name = particle->GetParticleName();
    ion.kineticEnergy = track->GetKineticEnergy();
    ion.position = track->GetPosition();
    ion.charge = particle->GetPDGCharge();

    WriteIonToFile(ion);
  }
}

void MySteppingAction::WriteIonToFile(const IonInfo& ion)
{
  std::ofstream csvFile;
  csvFile.open("created_ions.csv", std::ios::app);

  if (!csvFile) {
    std::cerr << "Unable to open file\n";
  }
  else {
    if (!ionHeaderWritten) {
      csvFile << "Step Number,Track ID,Name,Charge,Kinetic Energy (keV),Position X (mm),Position Y (mm),Position Z (mm)\n";
      ionHeaderWritten = true;
    }

    csvFile << ion.stepNumber << ","
            << ion.trackID << ","
            << ion.name << ","
            << ion.charge << ","
            << ion.kineticEnergy/keV << ","
            << ion.position.x() << ","
            << ion.position.y() << ","
            << ion.position.z() << "\n";
  }

  csvFile.close();
}

void MySteppingAction::WriteGeneratedParticleToFile(const G4Track* track)
{
  std::ofstream csvFile;
  csvFile.open("generated_particles.csv", std::ios::app);

  if (!csvFile) {
    std::cerr << "Unable to open file\n";
  }
  else {
    if (!genParticleHeaderWritten) {
      csvFile << "Step Number,Track ID,Name,Kinetic Energy (keV),Position X (mm),Position Y (mm),Position Z (mm)\n";
      genParticleHeaderWritten = true;
    }
    G4ParticleDefinition* particle = track->GetDefinition();

    csvFile << track->GetCurrentStepNumber() << ","
            << track->GetTrackID() << ","
            << particle->GetParticleName() << ","
            << track->GetKineticEnergy()/keV << ","
            << track->GetPosition().x() << ","
            << track->GetPosition().y() << ","
            << track->GetPosition().z() << "\n";
  }

  csvFile.close();
}

here is the github link with the whole project
atmospheric_ions

Thank you so much in advance, I would really appreciate any tips

2

Hello,

inside Geant4 there are only one model included in all Physics List , which describe muon-nuclear reactions. Cross section is relatively small, so normally in stepping action you will see whatever muon reactions and rarely C12 or C13 production. We never see user report with analysis of accuracy of Geant4 models for this type of reaction.

VI