RE: [fluka-discuss]: Transport of primary photons below 1 keV

From: Paola Sala <paola.sala_at_mi.infn.it>
Date: Thu, 3 May 2018 09:20:11 +0200

Dear Thomas
Electrons below 1 keV are not transported. They can be produced or not,
depending on the production mechanism.

Indeed, you should NOT score E+&E- doses, exactly because they are
threshold-dependent. The total dose instead contains the contribution of
these electrons that would have been produced in real world, while they
are not produced in the montecarlo. These contributions are scored as
pointwise energy depositions by photons.

Hope this helps
regards
Paola

> Dear Paola,
>
> Thank you very much for your answer, I just have an additional question
> but before, I will explain you why I need to do this to be more specific.
>
> The objective is to compute dose for a source at 1 cm from the scoring
> position.
> I know that gamma dose is an indirect dose and is in fact coming from
> energy transmitted in electrons of the medium.
> Then, the dose scored is the energy deposition of these electrons in the
> medium.
> It is why I score E+&E- doses.
> I score the E+&E- dose in GeV/g/pr and then transform it in Sv/h/pr.
> I observed that, for primary gamma of some MeV the E+&E- dose is very
> close to the one of gamma of 1 keV.
> So I wanted to be sure wether I can or not neglect doses coming from gamma
> below 1 keV.
>
> Now is my additional question:
> I tried to do the calculation as you suggested but I don't have any result
> (value = 0, uncertainty = 0).
> I score E+&E- doses for gamma emitted at 990 eV for example, and I use the
> following options in EMFCUT:
> -Production ant transport threshold for gamma 0.5 keV
> -Production and transport threshold for e+e- 0.5 keV
> Unfortunately, it seems that electrons are not simulated.
> Are secondary electrons below 1 keV transported/produced?
> Do you have an idea or a tip to perform this calculation?
>
> I thank you,
> Best regards,
> Thomas
>
> -----Original Message-----
> From: Paola Sala <paola.sala_at_mi.infn.it>
> Sent: Wednesday, April 25, 2018 1:01 PM
> To: Thomas Frosio <thomas.frosio_at_cern.ch>
> Cc: fluka-discuss_at_fluka.org
> Subject: Re: [fluka-discuss]: Transport of primary photons below 1 keV
>
> Dear Thomas
> in the last release, the hard limit for photons transport is 100 eV , you
> should be able to set it via EMFCUT (please check..) With limitations on
> the validity of models at these energies, be careful!
> In this context, may I ask why do you need to go below 1 keV?
> Regards
> Paola
>> Dear fluka team,
>>
>> I am trying to simulate the transport and energy deposition of photons
>> below 1 keV (500 eV- 1 keV).
>> I know that the minimum recommended energy is 5-10 keV for primary
>> photons and that transport of primary photons is limited to 1 keV.
>> However, is there any tip to be able to transport photons below 1 keV?
>>
>> I thank you in advance,
>> Best regards,
>> Thomas
>>
>>
>
>
> Paola Sala
> INFN Milano
> tel. Milano +39-0250317374
> tel. CERN +41-227679148
>
>
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>


Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148

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Received on Thu May 03 2018 - 11:19:31 CEST

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