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

From: Alfredo Ferrari <alfredo.ferrari_at_cern.ch>
Date: Sat, 16 Nov 2013 11:14:31 +0100

If you are looking at energy deposition spectra obviously you cannot use
LAM-BIAS! Whichever biasing is destroying the possibility of pulse height
spectra.

I do not know if this is the reason for your problem but it is surely
wrong. Also it would be much better to start from the PRECISIO default


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On Fri, 15 Nov 2013, Vittorio Boccone wrote:

> 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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>
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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 - 12:12:50 CET