Message: Re: results very sensitive to step size Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

Feedback Re: results very sensitive to step size 

Forum: Event and Track Management
Re: Question results very sensitive to step size (Cristian Bungau)
Re: None Re: results very sensitive to step size (michel maire)
Date: 13 Nov, 2010
From: Cristian Bungau <Cristian Bungau>

Dear Vladimir, Michel,

Thank you both for your replies. To limit the step size I am doing two things:

1. in my PhysicsList I add:

  while ((*theParticleIterator)()) {
.........

    G4ParticleDefinition* particle = theParticleIterator->value();
    G4ProcessManager* pmanager = particle->GetProcessManager();
    G4String particleName = particle->GetParticleName();

    if (particleName == "pi+") pmanager->AddProcess(new G4StepLimiter,  -1,-1,3);

    else if (particleName == "proton")  pmanager->AddProcess(new G4StepLimiter,  -1,-1,3);
.........

}

2. in my DetectorConstruction I add at the end:

target_log->SetUserLimits(new G4UserLimits(100.*micrometer));

and the /tracking/verbose 1 command output confirms that the 800 MeV protons are tracked in 100 micrometer steps.

Removing the target_log->SetUserLimits(new G4UserLimits(100.*micrometer)); condition results in fewer positive pions decaying at rest inside the thin target. I have also found that the difference in +ve pions decaying at rest with and without this condition is increasing with incident proton energy. I checked from incident energy of 250 MeV (where I found not much difference) to 3 GeV (where it made a bigger difference).

Best regards,

Cristian

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

1 None: Re: results very sensitive to step size   (michel maire - 15 Nov, 2010)
2 None: Re: results very sensitive to step size   (michel maire - 16 Nov, 2010)
1 Feedback: Re: results very sensitive to step size   (Cristian Bungau - 16 Nov, 2010)
(_ None: Re: results very sensitive to step size   (michel maire - 16 Nov, 2010)
3 Feedback: Re: results very sensitive to step size   (Gumplinger Peter - 16 Nov, 2010)
1 More: Re: results very sensitive to step size   (Cristian Bungau - 16 Nov, 2010)
 Add Message Add Message
to: "Re: results very sensitive to step size"

 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 ]