Why is there no interaction between particles and liquid argon in the simulation?

Physics Processes, Models and Cross Sections
1

Hello, I recently modified the B4a example to build a liquid argon detector. In my simulation, the liquid argon is contained in a stainless steel vessel. When I shoot electrons into it, I observe that the only process happening in the liquid argon is “transportation”, while in the stainless steel there are electromagnetic processes such as msc and bremsstrahlung. I would like to understand why it seems that my particles are not interacting with the liquid argon.
The material I am using is ‘lAr’ from the Geant4 material library.

  nistManager->FindOrBuildMaterial("G4_lAr");

Some output information:

 Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
G4WT1 >     0        0        0     -250        10        0        0         0       World initStep
G4WT0 >     0        0        0     -250        10        0        0         0       World initStep
G4WT1 >     1        0        0      250        10 1.52e-23      500       500 LiquidArgon Transportation
G4WT0 >     1        0        0      250        10 1.52e-23      500       500 LiquidArgon Transportation
G4WT1 >     2        0        0      250        10        0        0       500       World Transportation
G4WT0 >     2        0        0      250        10        0        0       500       World Transportation
G4WT1 >     3        0        0      250        10        0        0       500        Tank Transportation
G4WT0 >     3        0        0      250        10        0        0       500        Tank Transportation
G4WT1 >     4    0.102   0.0874      251      9.19    0.662    0.698       501        Tank eBrem
G4WT0 >     4   -0.111  -0.0485      251      7.97    0.938     0.92       501        Tank eBrem

_Geant4 Version:10.6.2
Operating System:
Compiler/Version:
CMake Version:

2

Hi @dengmanna

Thank you for your question.

There are few things that may be worth to be checked:

  • please check for overlaps, /geometry/test/run [1]
  • please try single thread
  • could you please clarify what physics is being used?

Using the example extended/electromagnetic/TestEm5, I get a stopping power value of 1.9 MeV g / cm2 for 10 MeV electron in G4_lAr (G4 version 11.3), similar to that from ESTAR database 2 MeV g / cm2.

Thank you for your time.

Best,
Alvaro

[1] Detecting Overlapping Volumes — Book For Application Developers 11.3 documentation

3

Thank you so much for replying me. And I’m so sorry for replying after so long.

I check for overlaps, and the output information is as follow.

image
image914×137 4.96 KB

And this is my physicsList:

#include “PhysicsList.hh”

#include “G4DecayPhysics.hh”

#include “G4EmStandardPhysics.hh”

#include “G4RadioactiveDecayPhysics.hh”

#include “G4HadronInelasticQBBC.hh”

namespace B4

{

//…oooOO0OOooo…oooOO0OOooo…oooOO0OOooo…oooOO0OOooo…

PhysicsList::PhysicsList()

{

SetVerboseLevel(1);

// Default physics

RegisterPhysics(new G4DecayPhysics());

// EM physics

RegisterPhysics(new G4EmStandardPhysics());

// Radioactive decay

RegisterPhysics(new G4RadioactiveDecayPhysics());

RegisterPhysics( new G4HadronInelasticQBBC());

}

//…oooOO0OOooo…oooOO0OOooo…oooOO0OOooo…oooOO0OOooo…

PhysicsList::~PhysicsList()

{

}

//…oooOO0OOooo…oooOO0OOooo…oooOO0OOooo…oooOO0OOooo…

void PhysicsList::SetCuts()

{

G4VUserPhysicsList::SetCuts();

}

//…oooOO0OOooo…oooOO0OOooo…oooOO0OOooo…oooOO0OOooo…

}