Controlling atomic deexcitation in multiple regions

[bloer]

I’m using geant 10.5.p01. I am trying to set up an application with multiple regions, with strict production cuts far from the sensitive region. This is mostly straightforward, but I cannot seem to configure atomic deexcitation to obey these cuts. I’m doing the following:

1. In my main:

  fPhysList = fFactory->GetReferencePhysList("Shielding");
  G4EmParameters* params = G4EmParameters::Instance();
  params->SetFluo(true);
  params->SetAugerCascade(false);
  params->SetAuger(false);
  params->SetPixe(false);
  //params->SetDeexActiveRegion("World", true, false, false);
  //just tune your cuts, rather than the heavy-handed stuff
  params->SetDeexcitationIgnoreCut(false);
  //make gammas follow cuts
  params->SetApplyCuts(true);
  params->Dump();
  
  //update the run manager
  fRunManager->SetUserInitialization(fPhysList);

2. In my UserDetectorConstruction::Construct():

  G4EmParameters* params = G4EmParameters::Instance();
  params->SetDeexActiveRegion("wallregion", true, false, false);
  params->AddPhysics("wallregion", "G4EmStandard");

  params->SetDeexActiveRegion("Hires", true, true, true);
  params->SetLowestMuHadEnergy(0);
  params->SetLowestElectronEnergy(10*eV);
  params->AddPhysics("Hires", "G4EmStandard_opt4");
  params->Dump();

Both of the Dump calls give the same output:

=======================================================================
======                 Atomic Deexcitation Parameters          ========
=======================================================================
Fluorescence enabled                               1
Fluorescence Bearden data files enabled            0
Auger electron production enabled                  0
Auger cascade enabled                              0
PIXE atomic de-excitation enabled                  0
De-excitation module ignores cuts                  0
Type of PIXE cross section for hadrons             Empirical
Type of PIXE cross section for e+-                 Livermore

That’s what I expect. Great! But a few lines later in the output from initializing the run, I get

### ===  Deexcitation model UAtomDeexcitation is activated for 4 regions:
          DefaultRegionForTheWorld  0  0  0
          Hires  1  0  0
          cryoregion  0  0  0
          wallregion  1  0  0
### ===  Auger cascade flag: 1
### ===  Ignore cuts flag:   1

So something has turned on Auger cascades and set deexcitation to ignore cuts! AND the flags I gave to enable Auger and PIXE in the Hires region were apparently lost somewhere. Further down, I get

=======================================================================
======       Radioactive Decay Physics Parameters              ========
=======================================================================
Max life time                                     1.4427e+06 ps
Internal e- conversion flag                       1
Stored internal conversion coefficients           1
Enable correlated gamma emission                  0
Max 2J for sampling of angular correlations       10
Atomic de-excitation enabled                      1
Auger electron emission enabled                   1
Auger cascade enabled                             1
Check EM cuts disabled for atomic de-excitation   1
Use Bearden atomic level energies                 0
=======================================================================

further confirming that my settings have been overridden. And to confirm again, I put /process/em/printParameters right before /run/beamOn, and I get

=======================================================================
======                 Atomic Deexcitation Parameters          ========
=======================================================================
Fluorescence enabled                               1
Fluorescence Bearden data files enabled            0
Auger electron production enabled                  1
Auger cascade enabled                              1
PIXE atomic de-excitation enabled                  0
De-excitation module ignores cuts                  1
Type of PIXE cross section for hadrons             Empirical
Type of PIXE cross section for e+-                 Livermore

And unsurprisingly if I put Pb210 primaries in the wallregion, I get a bunch of Auger particles:

    :----- List of secondaries ----------------
G4WT1 >            Bi210:  energy =0.1158 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy = 373.1 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy = 55.57 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy = 29.92 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy = 12.88 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy = 29.92 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy = 52.38 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy = 106.3 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy =   175 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy = 244.4 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy =   309 eV   time =3.26e+08 s 
G4WT1 >               e-:  energy = 2.586 keV  time =3.26e+08 s 
G4WT1 >               e-:  energy = 42.53 keV  time =3.26e+08 s 
G4WT1 >     :------------------------------------------

Even worse, if I call /process/em/deexcitationIgnoreCut false in my macro after initialization, I still get these. I have to explicitly say /process/em/auger false. I can’t find any command to make the radioactive decay emissions obey cuts.

Summary

• How do I prevent my options from being overriden? If there’s no way to set an option before initialization that will stick, is there a hook somewhere that I can add code to be called post-initialization? I really don’t want to tell my users “you have to add these 5 lines to every macro that you run after /run/initialize to make it work”.
• Is deexcitation control by region actually possible? What is the correct recipe?

[Sebastian_Santana]

Hello
I was reviewing the Geant4 atomic de-excitation model to implement it in a crystalline compound. Aiming to generate from protons a fluorecence process.

I am very concerned about the region where the deexcitation is generated, as you show in the image. My question is:

How do I associate the region where I want the deexcitation to exist? Do I use the solid, physical volume or do I use the logical volume?

And the second question is:

How do you make the call to the physical list to use inside the “params” since you do it with a string variable?

Is it necessary to add the physics.hh corresponding to these physics lists?

[Sebastian_Santana]

Here I show the conditions I use in my macro commands for de-excitation.

Are they well applied to both geometries?

and the other thing is that I only need fluorescence processes, should I activate pixe and fluo? because if I activate only fluo I don’t get tracks associated to gammas or electrons, only the proton hioni steps.

Thank you very much for your help.

[Sebastian_Santana]

[civanch]

Hello,

“wallreagion” should be G4Region name. In geometry description you should create G4Region and attach to it needed logical volume. A simple example : $G4INSTALL/examples/extended/electromagnetic/TestEm8

VI

[Sebastian_Santana]

Thank you very much civanch

[jairMora]

Wow interesting

But I have a question, is the emission spectrum that comes from flourescence, is it in the visible or is it totally dependent on PIXE, i.e. X-Ray emission only?