Re: [fluka-discuss]: scoring specific particle of complex source

From: Paola Sala <paola.sala_at_mi.infn.it>
Date: Mon, 23 Nov 2015 16:26:40 +0100

Dear Roman

first of all..there is a mistake in the label of the plot on page 2. Units
are #/m2/s/sr/MeV : square meter, not square centimeters. I apologize for
this, expecially because I did the plot...

Also, from your and others' questions, we realized that the normalization
issues for GCR, including full normalization and NO-Normalization, need
some explaination in the manual, that should come soon.


More specifically on your question:
- the global normalization (integral over energy and angle) is provided
to you bay the GCR package. You can find the value in the output file,
just after the initialization part. In your case:
*** Fluxst: 4.6536045 ions/cm^2/s
Below this, you also have the equivalent flux per primary particle
(depends on emission radius)
*** Flux: 7.95774744E-04 Part/pr/cmq ***
Now, one takes the usrbdx results - first set, integrated over solid angle
: bdx=part/cmq/GeV/pr
divide by a factor 1000 in order to have results per MeV, multiply by a
factor 10^4 to have the results per square meter, and divide by the total
solid angle ( 2 pi in your case , one way scoring)
--> bdxa=bdx*10/2/pi

the final result will be
fig2=bdxa*Fluxst/Flux

Not exactly, because the flux on your scoring sphere is not the same as on
the source surface.
Hope this helps
Paola
> dear Paola,
>
> Although the atomic mass of the ion indeed was part of the issue, it seems
> like there is more to it than that. After I have included amu, the result
> become aligned horizontally but not vertically (yes, I do multiply flux by
> amu).
>
> The reason is possibly due to the way I calculate the normalization. I
> followed the Luigi's explanation here (under 5):
> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/8274.html
> Specifically he says "For a discrete distribution, the normalisation is
> given by" the sum of fluxes at specific energy times the bin width.
> However, I realized that the fluka source files izphiMV.spc have different
> bin widths and therefore, since different bin widths matter, I can't use
> the equation that Luigi showed me.
>
> Also, both izphiMV.spc files and the plot on page 2 of the fluka lecture
> are given as differential flux [#/cmq/s/sr/MeV] while the output of USRBDX
> is differential fluence [#/cmq/GeV/sr]. How and should I convert fluka
> result to the units of the plot?
>
> thank you,
>
> Roman
>  
>
> ________________________________________
> From: Paola Sala <paola.sala_at_mi.infn.it>
> Sent: Tuesday, November 17, 2015 11:11 PM
> To: Roman Savinov
> Cc: fluka-discuss_at_fluka.org
> Subject: Re: [fluka-discuss]: scoring  specific particle of complex source
>
> Dear Roman
> your scoring is correct,
> the difference is in the units:
>
> The plot in page 2 of the fluka lecture gives particle spectra in MeV/amu,
> that is energy per nucleon
>
> USRBDX (and USRYIELD) outputs are in GeV, total energy
>
> The difference in unit affects  the horizontal scale and the normalization
> by a factor (/ or *)  atomic mass of the ion specie
>
> Hope this helps
> Paola
>> dear Fluka experts,
>>
>>
>> What is the proper way to score a specific particle (say He or C) from a
>> composite source?
>>
>> I have GCR_IONF with WHAT(1)=6 meaning the source consist of H, He, ...,
>> B, C. I am scoring with USRBDX. Hydrogen comes out right because there
>> is
>> a "proton" option in the drop down menu in USRBDX but what should I do
>> to
>> score, say, Helium or Carbon?
>>
>> I tried to use AUXSCORE by choosing Heavyion in USRBDX and Z=6 in
>> AUXSCORE (or WHAT(2)=-600)
>>
>> The results doesn't match what I expect from here (pg.2):
>>
>> https://www.fluka.org/free_download/course/triumf2012/Lectures/AdvancedCosmicRays2012.pdf
>>
>> looks like Helium and Carbon spectras are shifted to the right and
>> scaled
>> down.
>>
>>
>>
>> <https://www.fluka.org/free_download/course/triumf2012/Lectures/AdvancedCosmicRays2012.pdf>thank
>> you,
>>
>>
>> Roman
>>
>>
>>
>>
>
>
> 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 Nov 23 2015 - 17:32:38 CET

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