Re: [fluka-discuss]: Simulate Fano theorem in Fluka

From: Ferreira De Almeida Lourenco, Ana <am.lourenco_at_ucl.ac.uk>
Date: Mon, 1 Feb 2016 15:36:16 +0000

Ola' Thiago,

Thank you very much for this. I will have a look into the files.

Best wishes,
Ana

________________________________________
De: Viana Miranda Lima, Thiago
Enviado: 1 de fevereiro de 2016 13:42
Para: Ferreira De Almeida Lourenco, Ana; Bouchard Hugo; paola.sala_at_mi.infn.it
Cc: fluka-discuss_at_fluka.org
Assunto: Re: [fluka-discuss]: Simulate Fano theorem in Fluka

Sorry I forgot to say, not only the presentation on the Wed but there are
also some other presentations about specific scenarios that may be useful.

Best wishes
Thiago

On 01/02/2016, 12:00, "owner-fluka-discuss_at_mi.infn.it on behalf of
Ferreira De Almeida Lourenco, Ana" <owner-fluka-discuss_at_mi.infn.it on
behalf of am.lourenco_at_ucl.ac.uk> wrote:

>Dear Paola and Hugo,
>
>Thank you very much for your e-mails!
>
>Unfortunately, I'm not familiar with writing routines. Since CYLI-VOL
>gives a spatially uniform distribution in volume and I need an uniform
>source by mass, could you please give me some advice how I should do
>this? Any examples that you could provide would be greatly appreciated!
>
>Many thanks,
>Ana
>________________________________________
>De: Paola Sala <paola.sala_at_mi.infn.it>
>Enviado: 31 de janeiro de 2016 11:58
>Para: Bouchard Hugo
>Cc: paola.sala_at_mi.infn.it; Ferreira De Almeida Lourenco, Ana;
>fluka-discuss_at_fluka.org
>Assunto: Re: [fluka-discuss]: Simulate Fano theorem in Fluka
>
>Dear Hugo, Ana,
>thank you for pointing to your paper. If I understand correctly, you kill
>all processes, from nuclear interactions to e-m transport. It seems to me
>that the only MonteCarlo aspect that is tested is the stopping power
>description, that does not depend on density (for non-relativistic
>particles). Multiple (or single) scattering can have a role, and I doubt
>that that "angle-dependent" quantities intrinsically violate the Fano
>theorem.
>But probably we can continue or discussion offline, not to spam the list.
>Going to technical questions,
>-CYLI-VOL gives a spatially uniform distribution in volume. If you need to
>do by mass, I'm afraid you'll need to write your own user routine.
>-definitely do NOT use Corrfact
>-for best prcision, activate single scattering everywhere and all the
>corrections with the MULSOPT card.
>Ciao
>Paola
>> Dear Paola
>>
>> Sorry if I introduce myself in the conversation (I am co-supervising
>> Ana’s project). I just want to make sure we understand each other.
>>There
>> are basically 2 ways the Fano test can be done (in respect to Fano’s
>> theorem). One way is using an external parallel beam, in which case the
>> primary particles need to be “regenerated" at the site of primary
>> interaction. For protons, this is not possible (due to CSDA) and
>>therefore
>> you need to create a virtual particle that triggers proton transport in
>> the phantom (Sterpin et al, Med Phys 2014). The other way is simply to
>> create a homogeneous source of particle, similarly to a radionuclide. In
>> such source, particles are generally homogeneously (per unit mass) and
>> they are sampled from angular and energy distributions which do not
>>change
>> throughout the phantom. Such test is more suitable for charged particles
>> and this is what we want to use.
>>
>> So what Ana needs is :
>>
>> 1. A phantom with homogeneous atomic properties (cross sections,
>>I-value,
>> density effect parameter, etc.), but varying mass densities (her ion
>> chamber setup will be overriden to water-property materials but keeping
>> their original mass density). Thus, there must be a way to override the
>> density effect parameter or any other density-dependent property.
>>
>> 2. A homogeneous source such that the number of particle per unit mass
>> generated in the geometry is uniform in space.
>>
>> These 2 conditions allow Fano’s theorem to apply.
>>
>>
>> Many thanks for your support!
>>
>> With best regards
>> --
>> Hugo Bouchard, PhD, MCCPM
>> Professeur adjoint
>> Département de physique
>> Université de Montréal
>> Pavillon Roger-Gaudry bureau V-220
>> Tél: 514-343-6111 - ext. 34879
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On 2016-01-27, 2:19 AM, "Paola Sala" <paola.sala_at_mi.infn.it> wrote:
>>
>>>Dear Ana
>>>
>>>maybe I'm missing the context, but I do not think that the procedure you
>>>mention is the correct one to simulate the Fano theorem.
>>>
>>>The Fano theorem is usually applied to the study of small cavities at
>>>low
>>>density ( like TEPC detectors) for dosimetry. The smallness ensures
>>>that
>>>the particle fluence is not perturbed by the cavity. To test this, the
>>>"source" should be external, like a broad beam irradiation. The beam
>>>should not be relativistic (density effects are present at relativistic
>>>energies), The transport thresholds should be set at the same energy in
>>>all the volumes, and low enough when compared to the detector dimensions
>>>and density. The CORRFACT card shall NOT be used, non-relativistic cross
>>>sections are already density independent.
>>>
>>>Ciao
>>>Paola
>>>
>>>> Dear Fluka experts,
>>>>
>>>>
>>>> I would like to test Fano theorem in FLUKA.
>>>>
>>>>
>>>> ("Fano theorem states that under charged particle equilibrium
>>>> conditions,
>>>> the charged particle fluence is independent of the mass density of the
>>>> media as long as the cross-sections are uniform." from Sterpin et al
>>>> 2015)
>>>>
>>>>
>>>> I have a few questions:
>>>>
>>>> 1- Will it be possible to simulate Fano theorem in FLUKA?
>>>>
>>>>
>>>> 2- For that, I would have to simulate an uniform source per unit mass.
>>>> What would be the best way to simulate this in FLUKA? I was planning
>>>>to
>>>> use a BEAMPOSit card with SDUM=CYLI-VOL. Will this simulate an uniform
>>>> source per unit mass or volume?
>>>>
>>>>
>>>> 3- Also, how can I be sure that the cross sections are independent of
>>>> the
>>>> density? Should I use the CORRFACT card?
>>>>
>>>>
>>>> Many thanks,
>>>>
>>>> Ana
>>>>
>>>
>>>
>>>Paola Sala
>>>INFN Milano
>>>tel. Milano +39-0250317374
>>>tel. CERN +41-227679148
>>>
>>
>
>
>Paola Sala
>INFN Milano
>tel. Milano +39-0250317374
>tel. CERN +41-227679148
>
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Received on Mon Feb 01 2016 - 17:50:46 CET

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