_Geant4 Version: 4-11.2
_Operating System: Windows 11
_Compiler/Version: Visual Studio 17.9
_CMake Version: 3.29.2
Hello! I am trying to simulate the decay of 222Rn to the stable 206Pb isotope (my World volume is just a cubic meter of air). I am running into a few issues though. The first issue is that when I input “/process/list”, I get “Transportation, Decay, Radioactivation, Radioactivation”. It seems as though Radioactivation is initialized twice and for the life of me I cannot figure out why this would be.
Secondly, When I run the simulation for a single isotope of 222Rn, my output shows the branching ratio tables and decay chains properly all the way from 222Rn → 206Pb. However, in output for particle types, the only true daughter that ever shows up is 206Pb. The rest of the outputs are just the betas, gammas, alphas, etc. A snippet of the output is below along with my relevant code.
SECONDARY PARTICLE DETECTED: e-, Energy: 13.1754 keV, Time: 995.947 ms , Created by process: Radioactivation
SECONDARY PARTICLE DETECTED: anti_nu_e, Energy: 335.285 keV, Time: 995.947 ms , Created by process: Radioactivation
SECONDARY PARTICLE DETECTED: gamma, Energy: 803.052 keV, Time: 995.947 ms , Created by process: Radioactivation
G4VRestDiscreteProcess::PostStepGetPhysicalInteractionLength() - [ Radioactivation]
Particle type - Pb206
mass: 191.823[GeV]
charge: 82[e]
Direction x: 0.493406, y: 0.448836, z: -0.745048
Total Momentum = 0.00080305[GeV]
Momentum: 0.00039623[GeV], y: 0.000360437[GeV], z: -0.00059831[GeV]
Total Energy = 191.823[GeV]
Kinetic Energy = 1.68095e-09[GeV]
MagneticMoment [MeV/T]: 0
ProperTime = 0[ns]
in Material G4_AIR
InteractionLength= 0[cm]
G4RadioactiveDecay::DecayIt : Pb206 is not an ion or is outside (Z,A) limits set for the decay. Set particle change accordingly.
SECONDARY PARTICLE DETECTED: Pb206 (Z=82, A=206), Energy: 1.68095 eV , Time: 995.947 ms , Created by process: Radioactivation
SECONDARY PARTICLE DETECTED: gamma, Energy: 363.346 keV, Time: 995.947 ms , Created by process: Radioactivation
SECONDARY PARTICLE DETECTED: e-, Energy: 692.437 keV, Time: 995.947 ms , Created by process: Radioactivation
SECONDARY PARTICLE DETECTED: anti_nu_e, Energy: 19.3659 keV, Time: 995.947 ms , Created by process: Radioactivation
SECONDARY PARTICLE DETECTED: gamma, Energy: 803.052 keV, Time: 995.947 ms , Created by process: Radioactivation
PhysicsList
#include "PhysicsList.hh"
#include "G4DecayPhysics.hh"
#include "G4RadioactiveDecayPhysics.hh"
#include "G4SystemOfUnits.hh"
#include "G4UImanager.hh"
PhysicsList::PhysicsList() {
SetVerboseLevel(2);
// Register physics processes
RegisterPhysics(new G4DecayPhysics());
RegisterPhysics(new G4RadioactiveDecayPhysics());
}
void PhysicsList::ConstructProcess() {
G4VModularPhysicsList::ConstructProcess();
G4UImanager* UImanager = G4UImanager::GetUIpointer();
UImanager->ApplyCommand("/process/list"); // Display processes for debugging
}
Main
#include "G4RunManager.hh"
#include "G4UImanager.hh"
#include "G4VisExecutive.hh"
#include "G4UIExecutive.hh"
#include "DetectorConstruction.hh"
#include "PhysicsList.hh"
#include "ActionInitialization.hh"
int main(int argc, char** argv) {
G4UIExecutive* ui = nullptr;
if (argc == 1) ui = new G4UIExecutive(argc, argv);
G4RunManager* runManager = new G4RunManager();
// Set initialization classes
runManager->SetUserInitialization(new DetectorConstruction());
runManager->SetUserInitialization(new PhysicsList());
runManager->SetUserInitialization(new ActionInitialization());
// Initialize
runManager->Initialize();
// Visualization
G4VisManager* visManager = new G4VisExecutive();
visManager->Initialize();
G4UImanager* UImanager = G4UImanager::GetUIpointer();
if (ui) {
UImanager->ApplyCommand("/control/execute init_vis.mac");
//UImanager->ApplyCommand("/tracking/verbose 1");
//UImanager->ApplyCommand("/process/had/rdm/verbose 1");
ui->SessionStart();
delete ui;
}
delete visManager;
delete runManager;
return 0;
}
PrimaryGeneratorAction
#include "PrimaryGeneratorAction.hh"
#include "G4ParticleTable.hh"
#include "G4IonTable.hh"
#include "G4Event.hh"
#include "G4RandomTools.hh"
#include "G4SystemOfUnits.hh"
#include "G4GeneralParticleSource.hh"
#include <cmath>
PrimaryGeneratorAction::PrimaryGeneratorAction() {
fParticleGun = new G4ParticleGun();
//particleGun = new G4GeneralParticleSource();
}
PrimaryGeneratorAction::~PrimaryGeneratorAction() {
delete fParticleGun;
//delete particleGun;
}
void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent) {
G4int Z = 86; // 86 radon
G4int A = 222; // 222 Mass number
G4ParticleDefinition* radon = G4IonTable::GetIonTable()->GetIon(Z, A, 0.0);
fParticleGun->SetParticleDefinition(radon);
fParticleGun->SetParticlePosition(G4ThreeVector(0, 0, 0));
// Important: Set momentum direction to non-zero vector
// This helps ensure the particle is properly tracked
fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0, 0, 0.001));
// Set to very low energy (nearly at rest)
fParticleGun->SetParticleEnergy(0.0);
// Generate the vertex
fParticleGun->GeneratePrimaryVertex(anEvent);
}
RunAction
#include "RunAction.hh"
#include "G4Run.hh"
#include "G4RunManager.hh"
#include "G4UImanager.hh"
#include "G4UnitsTable.hh"
#include "G4SystemOfUnits.hh"
RunAction::RunAction() : G4UserRunAction() {}
RunAction::~RunAction() {}
void RunAction::BeginOfRunAction(const G4Run* run) {
G4cout << "Starting Run " << run->GetRunID() << G4endl;
// Get UI manager to send commands
G4UImanager* UImanager = G4UImanager::GetUIpointer();
UImanager->ApplyCommand("/run/initialize");
UImanager->ApplyCommand("/process/had/rdm/thresholdForVeryLongDecayTime 1.0e+60 year");
UImanager->ApplyCommand("/process/had/rdm/verbose 2");
UImanager->ApplyCommand("/process/had/rdm/analogueMC 0");
}
void RunAction::EndOfRunAction(const G4Run* run) {
G4cout << "Run " << run->GetRunID() << " completed." << G4endl;
}