Re: Re: LET Spectrum

...I would like to add a very interesting comment of Andrea Mairani
(thanks), that gave me an example of calculation of LET spectra where the
scoring of particles *emerging* from inelastic interactions is very
useful.
This is the case of fragmentation experiments on thick targets, where the
energy of the fragments is measured (tipically with TOF techniques) taking
into account approximatly the effect of the energy losses and the
re-interactions of these secondaries.
In this case it is important to have a characterization of the LET
distributions of the fragments not only at the measured point (at the
boundary crossing of interest) but also as they are emerging from the
inelastic interactions.

Coming back to our case, if our goal is to determine some probability
of radiation damage then we are not interested in the evaluation
of the "true value" of the particle charge distribution of all the emerging
secondaries, but we must evaluate the LET spectrum where we need, that is
at the most significative boundary crossing.

Hope it can be useful,
Regards,

 Anna

>
> Dear Mojdeh Najm,
>
> first of all please give a look to your geometry: it seems to me that your
> regions target1 and target2 are overlapping (you defined two RCC
> with the same radius one containing the other, but in the region
> definition
> you forgot to subtract...).
>
> Coming to the LET spectra, if you want to select the contribution of
> hadron=
> s
> with energy > 20 MeV it seems to me reasonable to use the generalized
> particle HADG20M.
> As you wrote your first quantity in USRYIELD will be the LET, having in
> mind (see for example
> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/1250.html)
> that LET bins are given in keV/(micron g/cm^3). You have to choose a
> reasonable interval.
> The bin contents will be normalized to the unit interval of your second
> variable (GeV in your case, if you use kinetic energy), because the
> distributions are always expressed as double-differential, even if in the
> second variable we have only one bin. In your place I would set 20 MeV as
> lowest limit of the kinetic energy (it is not mandatory), due to the fact
> that you are already requiring this energy cut.
> At the end you will get d2N/dLETdE by setting what(6) with ixa=3D3 (plane
> double differential yield, it does not make sense to choose the cross
> section!).
>
> An observation more. You put What(4)=3D-1, What(5)=3D-2, so that you
> are scoring particles *emerging* from inelastic interactions in your two
> silicon targets. In my opinion you don't want to do this but you want to
> score the contribution to the LET of all the hadrons > 20 MeV... then I
> would set as scoring surface in USRYIELD the boundary crossing between the
> two parts of your target: you will get your LET distribution according
> with the layer thickness(see for ex.
> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/2215.html).
>
>
> Hope it helps,
> Regards,
>
> Anna
>
>
>
>
>> Dear All
>> I want to get LET spectra from USRYIElD with HADG20M as a particle.
>> (LE=
> T
>> spectrum means flux of particles vs. LET. ) I have some question about
>> setting of USRYIELD.
>>
>> 1) I set Particle LET as a first quantity(range:10-1000) and the second
>> quantity is the particles kinetic energy(1e-5 -1000 GeV for cosmic ray).
>> Are they right?
>>
>> 2) I defined HadG20M as a particle (for calculating single event upset).
>> Is
>> it Ok?
>>
>> 3) finally, what should I set as a =93kind=94?(dN or d sigma?)
>>
>> I attached inp and source file. I=92m looking forward to the answers.
>>
>> (Meanwhile, I set 4 difference types of USRYIELD, please tell me which
>> of
>> them is correct?)
>>
>> Regards
>>
>> Najm
>>
>
>
Received on Mon Sep 27 2010 - 17:36:12 CEST