Get interaction of a secondary particle

Particles, Track, Event, Run and Biasing
21

in the uploaded nohup.out, fSectrackID is always 0
but then you compare step->GetTrack()->GetTrackID() == fSectrackID, probably GetTrackID is never 0?

22

Hello @weller, I tried to do these prints:

  1. Printing all e+ produced by gamma->e+e- in the regenerator
for(size_t lp1=0;lp1<(*fSecondary).size(); lp1++){
     secondaryParticleName =  (*fSecondary)[lp1]->GetDefinition() -> GetParticleName();  // name of the secondary
     process = (*fSecondary)[lp1]-> GetCreatorProcess()-> GetProcessName();   // process creating it
     fSectrackID = (*fSecondary)[lp1]->GetTrackID(); //track id
     fSsecparID = (*fSecondary)[lp1]->GetParentID();   //parent id
     volumeName = (*fSecondary)[lp1] -> GetVolume() -> GetName(); // volume where secondary was generated 
     if (process=="conv" && secondaryParticleName =="e+"){	 
    G4cerr << G4endl;
     G4cerr << "Event nĀ°: " << lp1 << G4endl;
     G4cerr << "secondaryParticleName: " << (*fSecondary)[lp1]->GetDefinition() -> GetParticleName() << G4endl;
     G4cerr << "process: " << (*fSecondary)[lp1]-> GetCreatorProcess()-> GetProcessName() << G4endl;
     //G4cerr << "fSectrackID: " << (*fSecondary)[lp1]->GetTrackID() << G4endl;
     //G4cerr << "fSsecparID: " << (*fSecondary)[lp1]->GetParentID() << G4endl;
     G4cerr << "volumeName: " << (*fSecondary)[lp1] -> GetVolume() -> GetName() << G4endl;
     G4cerr << G4endl;
 
 }

and I get several particlesā€¦

    1. Printing all e+ produced by gamma->e+e- in the regenerator and outgoing it
for(size_t lp1=0;lp1<(*fSecondary).size(); lp1++){
     secondaryParticleName =  (*fSecondary)[lp1]->GetDefinition() -> GetParticleName();  // name of the secondary
     process = (*fSecondary)[lp1]-> GetCreatorProcess()-> GetProcessName();   // process creating it
     fSectrackID = (*fSecondary)[lp1]->GetTrackID(); //track id
     fSsecparID = (*fSecondary)[lp1]->GetParentID();   //parent id
     volumeName = (*fSecondary)[lp1] -> GetVolume() -> GetName(); // volume where secondary was generated 
     if (process=="conv" && secondaryParticleName =="e+"){
     	if(NextVol && ThisVol->GetName()=="Regenerator" && NextVol->GetName()=="World"){
		 
	 
    G4cerr << G4endl;
     G4cerr << "Event nĀ°: " << lp1 << G4endl;
     G4cerr << "secondaryParticleName: " << (*fSecondary)[lp1]->GetDefinition() -> GetParticleName() << G4endl;
     G4cerr << "process: " << (*fSecondary)[lp1]-> GetCreatorProcess()-> GetProcessName() << G4endl;
     //G4cerr << "fSectrackID: " << (*fSecondary)[lp1]->GetTrackID() << G4endl;
     //G4cerr << "fSsecparID: " << (*fSecondary)[lp1]->GetParentID() << G4endl;
     G4cerr << "volumeName: " << (*fSecondary)[lp1] -> GetVolume() -> GetName() << G4endl;
     G4cerr << G4endl;
 }
 }

but I donā€™t get any particleā€¦

it looks like that all positrons outgoing the regenerator are produced by other process (i.e. eBrem)ā€¦

but itā€™s strangeā€¦because in the project there is the idea to regenerate e+ from gamma conversionā€¦

23

in your nohup.out, the very last entry:

G4WT1 > Event nĀ°: 1
G4WT1 > secondaryParticleName: e+
G4WT1 > process: conv
G4WT1 > fSectrackID: 0
G4WT1 > fSsecparID: 588
G4WT1 > volumeName: Regenerator

is that what you are looking for?

24

Yesh Iā€™m looking for the
process =="conv" && volumeName=="Regenerator"

but

  1. Simulating 10000 events (instead, in the file that I uploaded I simulated only 100 events)
  2. I didnā€™t set selection on fSecparID and fSectrackIDā€¦
25

Correct me if Iā€™m wrong, but isnā€™t eBrem (Bremsstrahlung) a process where a gamma gets created (by decelleration of a charged particle)?

So maybe only the last process a positron/electron went through before leaving the volume under consideration is eBrem, but the positron could have originally been created via conv?
Probably it is highly unlikely for a conv process to happen very close to the surface (ratio of volume close to and far from the surface?), thatā€™s why you did not encounter at least one of them in your limited number of eventsā€¦

26

Hello @weller

Yes, when an Electron/positron moves near atomic nuclei, it can emits photons.

Obviously, itā€™s possible that a photon produces a positron then it emits photon so I get it as an ā€œeBreamā€ā€¦but how can I know if it was produce by a photon or, for example, by positron of primary beam??

Currently both the beam and secondary particles producded in the targets can reich the regenerarorā€¦
So I canā€™t know if the parent of the eBream is a photon or other particleā€¦I tried to add a magnetic field in order to deflect charged particles (i.e. to have only photons reaching the regenerator), but even if I donā€™t get errors, the simulation doesnā€™t run Add a magnetic field - #4 by faca87