Message: Problem with electron stopping power with the LowEnergy Package Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

Question Problem with electron stopping power with the LowEnergy Package 

Forum: Electromagnetic Processes
Date: 18 May, 2009
From: Isabelle Fonteille <Isabelle Fonteille>

 Attachment:
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2009/05/18/01.12-98811-electron.txt
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2009/05/18/00.54-66624-ueStandard_StepFun1um.gif
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2009/05/18/00.54-9017-eLivermore_StepFun1um.gif


Hello everyone,

In order to verify the accuracy of the stopping power of electrons in water,
I modified the code in the Stepping Action class of the TestEm18 example.
For each step, I keep in a TTree the energy before the step, the size of the step
and the energy loss (not deposit) during the step :

if ( ( step->GetTrack()->GetDefinition()->GetParticleName() == "e-") {
    G_EnergiePreStep[G_NbrInteractions] = step->GetPreStepPoint()->GetKineticEnergy();
    G_DeltaEnergieTotStep[G_NbrInteractions] = step->GetPreStepPoint()->GetKineticEnergy() - step->GetPostStepPoint()->GetKineticEnergy();
    G_DeltaXStep[G_NbrInteractions] = step->GetStepLength();
    G_DeltaETotSurDeltaXStep[G_NbrInteractions] = G_DeltaEnergieTotStep[G_NbrInteractions] / G_DeltaXStep[G_NbrInteractions] ;
}

After, with a root programme, I draw an a unique graph :
- G_DeltaETotSurDeltaXStep as a function of G_EnergiePreStep, for every kind of interaction (in gray on the figure)
- the collision and radiation stopping power of the NIST ESTAR database (respectively in red and blue on the figure)

I made a simulation with the attach file electron.txt, first with the standard PhysicList and then with the LowEnergy Livermore PhysicList. You can find as attach files the two figures of the result, where we can see :
 - with the standard PhysicList, the result correspond to theory
 - with the livermore PhysicList, there is an inchoerence for energies below ~2 or 3 keV.

Is there an explanation for this observation???


I also have another question : is the command /process/eLoss/StepFunction working with the LowEnergy packages??

Thanks for your help,
Isabelle


  
      

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

1 Idea: Re: Problem with electron stopping power with the LowEnergy Package   (Vladimir Ivanchenko - 18 May, 2009)
(_ None: Re: Problem with electron stopping power with the LowEnergy Package   (michel maire - 18 May, 2009)
 Add Message Add Message
to: "Problem with electron stopping power with the LowEnergy Package"

 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 ]