Re: [fluka-discuss]: Deposited energy from 70 MeV positrons on NaI

From: Vittorio Boccone <Vittorio.Boccone_at_cern.ch>
Date: Fri, 15 Nov 2013 22:22:42 +0000

Hi Mina and Luca,
  the EM part should not contain any peak. Can you give us more detail about the simulation (like the input file)?
Do you have in both simulation the same amount of material in front of the target?
How strong is the effect? Is it an effect that you can see in linear scale (macroscopic) or in log scale (small effect)?

Best
V.

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On 14 Nov 2013, at 23:37, Mina Nozar <nozarm_at_triumf.ca> wrote:
> Hello everyone,
> 
> A friend of mine at TRIUMF (cc'd above) asked me whether I could quickly setup 70 MeV positrons on a simple cylindrically shaped NaI and look at the total deposited energy distribution.  I had other pressing projects on my plate and had never looked at dep. energy on an event by event basis so it took me a little while.
> 
> 
> In the FLUKA project:
> 
> I am using NEW-DEFA for default (thresholds, etc),  pho-nuclear interactions turned on, as well as coalescence and evaporation.
> I have set production and transport energy cut offs to 100 keV (KE) for e+,e- and 10 keV for photons.
> I have used LAM-BIAS
>  - to reduce the inelastic interaction length by 0.02.
>  - to set the LPB to 1 MeV for e+,e-.
> 
> 
> That's about it.  But when we look at the deposited energy distribution (data + Geant4 + FLUKA), there are two broad bumps below the main peak in the data that is missing from the FLUKA results but somewhat reproduced by Geant4.
> 
> Does anyone know where this difference is coming from?  Have I not included some relevant physics in my simulation?
> 
> 
> Thanks and best wishes,
> Mina
> <data_fluka_G4.jpg>

Received on Sat Nov 16 2013 - 00:11:42 CET