Re: [fluka-discuss]: NIEL scaling

From: JAIRO MARTÍN ROJAS HUAMANÍ <a20122093_at_pucp.pe>
Date: Mon, 7 Sep 2015 22:04:38 -0500

Dear Alberto,

Thanks for your help, now I know where I was wrong.

My goal is to know the equivalence between the damage produced by my beam
with my particular spectrum and the number of 1 MeV neutrons, hurled from
the same position, that would make the same damage. I wonder if you could
recommend me a detailed method to do it. Thanks

2015-08-31 1:20 GMT-05:00 Alberto Fasso <Alberto.Fasso_at_cern.ch>:

>
> ________________________________________
> From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on
> behalf of JAIRO MARTÍN ROJAS HUAMANÍ [a20122093_at_pucp.pe]
> Sent: 31 August 2015 05:25
> Hi,
>
> > 1. The USRBIN call to 1 MeV neutron equivalent fluence (Si1MeVEq), which
> is in cm⁻² , has the same form of the beam, a circle. Being a function >
> related to the damage, should not this plot be different for different
> materials which are covered by the broad beam? (in the plot they have
> similar > color (value) for air and for the silicon chip).
>
> The subject of your e-mail is "NIEL scaling", but you did not score
> NIEL-DEP, an energy deposition which would depend on the material. You
> scored instead SI1MEVNE, which is the fluence that would produce a damage
> equal to that of 1-MeV neutrons in silicon. That fluence does not depend
> on the material.
>
> > 2. For the plot Neutron Fluence Cilinder, being normalized in
> Fluence/MeV, we would expect its integral to be 10⁶ as written in START,
> but we get > a lower number (240544.283).
>
> The number you input in START is a number of neutrons, not a fluence. A
> fluence is the density of neutron paths in cm/cm3
>
> From both your question, you seem not to have a clear idea of what a
> fluence is. Have a look at the lecture on
>
> https://indico.cern.ch/event/365567/contribution/23/attachments/726812/997350/07_Scoring_2015.pdfs
>
> Alberto
>
> To: fluka-discuss_at_fluka.org
> Subject: [fluka-discuss]: NIEL scaling
>
> Hi FLUKA users,
>
> Recently we have been working on FLUKA with the purpose of knowing the
> Neutron Fluence Equivalence of 1 MeV neutrons on a silicon chip. We use a
> given neutron spectrum (from a data file) and have designed a simple
> geometry with a cilinder surrounding the chip. When we simulate the process
> we find some features:
>
> 1. The USRBIN call to 1 MeV neutron equivalent fluence (Si1MeVEq), which
> is in cm⁻² , has the same form of the beam, a circle. Being a function
> related to the damage, should not this plot be different for different
> materials which are covered by the broad beam? (in the plot they have
> similar color (value) for air and for the silicon chip).
> 2. For the plot Neutron Fluence Cilinder, being normalized in Fluence/MeV,
> we would expect its integral to be 10⁶ as written in START, but we get a
> lower number (240544.283).
>
> Thanks you for your help.
>
> ps. We are attaching all the relevant files. To see the graphics you
> should first compile
>


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Received on Tue Sep 08 2015 - 05:04:38 CEST

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