Message: Neutron spallation numbers not adding up Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

Question Neutron spallation numbers not adding up 

Forum: Hadronic Processes
Date: 26 Nov, 2010
From: Cristian Bungau <Cristian Bungau>

Dear all,

I am trying to simulate the neutron yields from 1 GeV protons impact on a Th-232 target. In order to make sure I am getting the correct numbers, I split the output into these categories:

1. neutrons produced:

in SteppingAction ask: if(aStep->GetTrack()->GetCurrentStepNumber()==1 && aStep->GetTrack()->GetDefinition()->GetParticleName() == "neutron" && aStep->GetPreStepPoint()->GetTouchableHandle()->GetVolume()->GetName()=="target") neutrons_produced++;

2. neutrons escaping out from the target:

in SteppingAction ask: if(aStep->GetTrack()->GetDefinition()->GetParticleName() == "neutron" && aStep->GetTrack()->GetNextVolume() && aStep->GetPostStepPoint()->GetStepStatus() == fGeomBoundary && aStep->GetPreStepPoint()->GetTouchableHandle()->GetVolume()->GetName()=="target") neutrons_escaping++;

3.1 neutrons captured inside the target:

in SteppingAction ask: if(aStep->GetTrack()->GetDefinition()->GetParticleName() == "neutron" && aStep->GetPostStepPoint()->GetProcessDefinedStep() && aStep->GetPostStepPoint()->GetProcessDefinedStep()->GetProcessName()=="nCapture" && aStep->GetPreStepPoint()->GetTouchableHandle()->GetVolume()->GetName()=="target") neutrons_captured++;

3.2 elements produced in these neutron capture processes:

 if(aStep->GetTrack()->GetCurrentStepNumber()==1 && aStep->GetTrack()->GetCreatorProcess() && aStep->GetTrack()->GetCreatorProcess()->GetProcessName() == "nCapture" && aStep->GetPreStepPoint()->GetTouchableHandle()->GetVolume()->GetName()=="target" && aStep->GetTrack()->GetDefinition()->GetParticleName()!="gamma") G4cout << "Neutron capture in target produces " << aStep->GetTrack()->GetDefinition()->GetParticleName() << G4endl;

Now here are the numbers I get:

8559 neutrons produced inside target.

1882 neutrons escaping the target.

1829 neutrons captured inside the target.

95 Th233[0.0] elements produced in neutron capture events inside the target.

I would be very grateful if you could please help me understand two things:

a) how to interpret the big difference between (neutron_produced) and (neutron_escaping+neutron_captured);

b) why if 1892 neutrons are captured, only 95 elements (gammas were excluded in the IF condition 3.2, and since the proton target is Th-232 any neutron capture should result indeed in Th-233 and gammas) are produced in these neutron capture processes?

Thank you very much,

Best regards,

Cristian

Inline Depth:
 1 1
 All All
Outline Depth:
 1 1
 2 2
 All All
Add message: (add)

1 Sad: Re: Neutron spallation numbers not adding up   (Cristian Bungau - 28 Nov, 2010)
(_ Note: Re: Neutron spallation numbers not adding up   (Cristian Bungau - 29 Nov, 2010)
 Add Message Add Message
to: "Neutron spallation numbers not adding up"

 Subscribe Subscribe

This site runs SLAC HyperNews version 1.11-slac-98, derived from the original HyperNews


[ Geant 4 Home | Geant 4 HyperNews | Search | Request New Forum | Feedback ]