Runtime exception during execution, leading to a crash

[OdaiSuad]

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_Geant4 Version: 11.1
_Operating System: Windows 10
_Compiler/Version: Microsoft Visual Studio Community 2022 (64-bit) - Version 17.9.0
_CMake Version: 3.25.1

Hello everybody,

Could anyone help me identify the following error? (Please see the attached snapshots.)

I am attempting to simulate the mass attenuation coefficient for various materials, such as alloys, glass, etc. No compilation issues were raised (see attached photo 1) . However, a runtime exception occurred during execution, leading to a crash (see the attached photo 2).

Please note that I can run the B1 example without any issues.

Is there any advice? Thank in advance

[bmorgan]

The error message is telling you that a nullptr was passed to some call to G4ParticleGun::SetParticleDefinition(), so check for calls to this in your code and see how/why a nullptr is getting passed.

[OdaiSuad]

Thank you @bmorgan for your answer. I didn’t use G4ParticleGun::SetParticleDefinition() in my code. Maybe this is my mistake. I use the following function in my PrimaryGenerator.cc. Let me play with it and I will update you with my results.

PrimaryGeneratorAction::PrimaryGeneratorAction() {
    // Create particle gun
    particleGun = new G4ParticleGun(1);

    // Get particle table
    G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
    G4String particleName;
    G4ParticleDefinition* particle = particleTable->FindParticle(particleName = "gamma");
    particleGun->SetParticleDefinition(particle);

####################################################

My PrimaryGeneratorAction.cc file is:

#include "PrimaryGeneratorAction.hh"
#include "G4Event.hh"
#include "G4ParticleGun.hh"
#include "G4ParticleTable.hh"
#include "G4SystemOfUnits.hh"

PrimaryGeneratorAction::PrimaryGeneratorAction() {
    // Create particle gun
    particleGun = new G4ParticleGun(1);

    // Get particle table
    G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
    G4String particleName;
    G4ParticleDefinition* particle = particleTable->FindParticle(particleName = "gamma");
    particleGun->SetParticleDefinition(particle);
}

PrimaryGeneratorAction::~PrimaryGeneratorAction() {
    delete particleGun;
}

void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent) {
    // Set array of photon energies
    G4double photonEnergies[] = { 0.015, 0.1, 0.5, 1, 3, 5, 10, 15 }; // in MeV

    // Loop through each photon energy and generate primaries
    for (size_t i = 0; i < sizeof(photonEnergies) / sizeof(photonEnergies[0]); ++i) {
        G4double energy = photonEnergies[i] * MeV;

        // Set particle energy
        particleGun->SetParticleEnergy(energy);

        // Set particle position
        G4double positionX = 0.0;
        G4double positionY = 0.0;
        G4double positionZ = -5.0 * cm; // Position just above the source
        particleGun->SetParticlePosition(G4ThreeVector(positionX, positionY, positionZ));

        // Set particle direction
        G4double directionX = 0.0;
        G4double directionY = 0.0;
        G4double directionZ = 1.0;
        particleGun->SetParticleMomentumDirection(G4ThreeVector(directionX, directionY, directionZ));

        // Generate primary particle
        particleGun->GeneratePrimaryVertex(anEvent);
    }
}