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From: Paola Sala <paola.sala_at_mi.infn.it>

Date: Sun, 31 Jan 2016 12:58:57 +0100

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
*

*> Anaâ€™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 Fanoâ€™s
*

*> theorem). One way is using an external parallel beam, in which case the
*

*> primary particles need to be â€œregenerated" 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 Fanoâ€™s theorem to apply.
*

*>
*

*>
*

*> Many thanks for your support!
*

*>
*

*> With best regards
*

*> --
*

*> Hugo Bouchard, PhD, MCCPM
*

*> Professeur adjoint
*

*> DÃ©partement de physique
*

*> UniversitÃ© de MontrÃ©al
*

*> Pavillon Roger-Gaudry bureau V-220
*

*> TÃ©l: 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 Sun Jan 31 2016 - 14:20:34 CET

Date: Sun, 31 Jan 2016 12:58:57 +0100

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

Paola Sala

INFN Milano

tel. Milano +39-0250317374

tel. CERN +41-227679148

__________________________________________________________________________

You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info

Received on Sun Jan 31 2016 - 14:20:34 CET

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