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Particle reached max step number [message #19444] Thu, 18 August 2016 10:37 Go to next message
Oleg is currently offline  Oleg
Messages: 19
Registered: August 2016
Location: GSI
occasional visitor
From: *gsi.de
Hello,

the alpha particle in the gas produce many electrons but not so many as it should be.
The error is:
*** Particle reached max step number (15000). ***
Where one can set the maximum step number, let say 30000?
And eventually - increase the step size?

Oleg.
Re: Particle reached max step number [message #19445 is a reply to message #19444] Thu, 18 August 2016 10:53 Go to previous messageGo to next message
Dmytro Kresan is currently offline  Dmytro Kresan
Messages: 166
Registered: June 2004
first-grade participant
From: *gsi.de
In your case with actar simulations, you need to adjust two files in gconfig directory: g4GarfieldConfig.C and g4garfieldconfig.in

In first you can set maximum number of steps.
You can set only maximum step length. The minimum step size is controlled by energy cut for a specific particle / process, larger cut --> larger step size. Refer to Geant4 manual.

I saw also that you need to change garfield region in g4garfieldconfig.in to helium.

Best regards,
Dima
Re: Particle reached max step number [message #19446 is a reply to message #19445] Thu, 18 August 2016 11:07 Go to previous messageGo to next message
Oleg is currently offline  Oleg
Messages: 19
Registered: August 2016
Location: GSI
occasional visitor
From: *gsi.de
In g3GarfieldConfig.C:

//set geant4 specific stuff
geant4->SetMaxNStep(30000); // default is 30000

In g4garfieldconfig.in:

# Garfield simulation configuration
/mcPhysics/fastSimulation/setModel garfieldModel
/mcPhysics/fastSimulation/setParticles gamma e- alpha
/mcPhysics/fastSimulation/setRegions helium

This all does not help.
The step limit 15000 is set somewhere else.

Oleg.
Re: Particle reached max step number [message #19447 is a reply to message #19446] Thu, 18 August 2016 11:17 Go to previous messageGo to next message
Dmytro Kresan is currently offline  Dmytro Kresan
Messages: 166
Registered: June 2004
first-grade participant
From: *gsi.de
Yes, you are right. Another try.

15000 limit is set in the file macros/r3b/actar/r3ball.C :

Int_t nSteps = -15000;
gMC->SetMaxNStep(nSteps);


In addition, concerning step size. In the same directory the file g4config2.in (currently) :

/run/setCut 1. mm
/run/setCutForRegion ArCO2 1. um

Best regards,
Dima
Re: Particle reached max step number [message #19448 is a reply to message #19447] Thu, 18 August 2016 11:25 Go to previous messageGo to next message
Oleg is currently offline  Oleg
Messages: 19
Registered: August 2016
Location: GSI
occasional visitor
From: *gsi.de
In macros/r3b/actar/r3ball.C
there are few lines:

// ------ Increase nb of step for CALO
Int_t nSteps = -15000;
gMC->SetMaxNStep(nSteps);

I was sure it is related to the calorimeter and not our detector. Is it?

In macros/r3b/actar/g4config2.in:

/run/setCut 1. mm
/run/setCutForRegion helium 100. um

Regards, Oleg.

Re: Particle reached max step number [message #19449 is a reply to message #19448] Thu, 18 August 2016 11:36 Go to previous message
Dmytro Kresan is currently offline  Dmytro Kresan
Messages: 166
Registered: June 2004
first-grade participant
From: *gsi.de
I do not know who has put this comment there, but it is meaningless. The limit is set globally.

The cuts you have to adjust by testing.

Best regards,
Dima
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