Date: Wed, 20 Nov 2013 18:17:43 -0800 (PST)
Dear Alfredo,
Thank you.
I repeated the simulation without LAM-BIAS and used PRECISIO. I now see
the two structures (due to photon capture/single & double neutron
emission) below the main peak.
Best wishes,
Mina
> 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
>
>
> +----------------------------------------------------------------------+
> | Alfredo Ferrari || Tel.: +41.22.76.76119 |
> | CERN-EN/STI || Fax.: +41.22.76.69474 |
> | 1211 Geneva 23 || e-mail: Alfredo.Ferrari_at_cern.ch |
> | Switzerland || |
> +----------------------------------------------------------------------+
>
> 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.
>> --
>>
>> !!! Please take note that my main e-mail address will not be
>> !!! valid anymore starting from 1st January 2014.
>> !!!
>> !!! Please use those addresses instead:
>> !!! Professional: dr.vittorio.boccone_at_ieee.org
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>>
>> Dr. Vittorio Boccone - University of Geneva
>>
>> o Address:
>> UniGe: Département de physique nucléaire et corpusculaire
>> 24 Quai Ernest-Ansermet, CH-1211 Geneve 4, Switzerland
>> CERN: CERN, CH-1211 Geneve 23, Switzerland
>>
>> o E-mail:
>> dr.vittorio.boccone_at_ieee.org (professional)
>> vittorio.boccone_at_gmail.com (private)
>>
>> 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>
>>
>>
(image/jpeg attachment: NaI_DE_noLamBias.jpg)