Questions regarding Gammaknife example: no gammas are emitted

Getting Started
1

Geant4 Version: 11.3.2
Operating System: Pop!_OS 22.04 (Ubuntu based)
Compiler/Version: g++ 11.4.0
CMake Version: cmake 3.22.1

So I made a post regarding the gammaknife example before:

which fixed the problem of “command not found” upon executing /process/had/rdm command.

But after this, the gammaknife example shows no gamma emittion on screen or the resulting eDep file(Which shows all 0 on energy deposited), and gps angle & particles are all set on GPS.in file. And reading the source code seems like it’s setting up gps.

I’m using all default Macro files. Anyone know how to fix the issue?

2

Hej,

I think that example has not been updated since some changes in the past and for some reason its messenger doesn’t seem to be enough for adding radioactive decay.

Try adding the header:

#include "G4Radioactivation.hh"

and later add the following:

void GammaKnifePhysicsList::ConstructProcess()
{
  // transportation
...
...
...
 // register radioactiveDecay
  //
  G4Radioactivation* radioactiveDecay = new G4Radioactivation();
  G4PhysicsListHelper* ph = G4PhysicsListHelper::GetPhysicsListHelper();
  ph->RegisterProcess(radioactiveDecay, G4GenericIon::GenericIon());

}

this should ensure that the physics is as close as the original one and you get the radioactive decay enabled and the “ions” created correctly.

If you need more options for radioactive decay like atomic relaxation after internal convertion and so on, please check other examples. This one is a good start examples/extended/radioactivedecay/rdecay01.

Cheers,

/Pico

3

That didn’t fixed the issue. No ions are shot and I only see zeroes on the eDep file from start to finish. Maybe ions are not being shot at the detector correctly?

4

Update

I realized the macro file had an issue that wouldn’t allow the simulation to show trajectories.
This will show the gamma trajectories and the volume. You need to write this to the defaultMacro.mac

...
# Open a viewer
/vis/open
/vis/drawVolume
...

But I still don’t get energy deposition on eDep_scorer.out.
Can anyone tell me if it’s the example’s problem?

5

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