Re: [fluka-discuss]: Number of primaries when using source.f

From: Hamideh Jalali <jalali.hb_at_gmail.com>
Date: Wed, 5 Aug 2015 18:59:13 +0430

Dear Mary

I am thankful for your response.
Actually I got the flux.dat from SPECTRA computer program. As I mentioned
the first column is energy (E not dE) which is binned linearly,
so the bin width for all energy intervals is constant. As I realized, to
get the whole number of primaries I should add up the values of second
column(photon/second/energy) and multiply by the value of bin width(because
of the linearity binning the bin width is constant). Am I right?
Also for source.f, can I use the subroutine source which is modified for the
exercise 8 in 8th FLUKA course,with spectrum.dat file that has two columns
(first one is energy and second one is Photon/s)?

<http://goog_1002269095>
http://www.fluka.org/fluka.php?id=course&sub=program&navig=2&which=demokritos2009

Best Regards
Hamideh




On Mon, Aug 3, 2015 at 10:08 AM, me_at_marychin.org <me_at_marychin.org> wrote:

> Dear Hamideh,
>
> First thing to check is whether your the energy in your second column
> (photon/s/energy) is the energy (E), or the difference in energy or the bin
> width (dE). Both would have the same dimension and unit. The latter is
> typically used for histograms with logarithmic bins, as in lethargy plots.
> For the latter case, one would multiply with the corresponding bin width to
> get the count for each bin.
>
> Getting the above right is important for sampling the energy correctly in
> source.f, and also for understanding how many photons are there per second.
>
> :) mary
>
>
> On 02 August 2015 at 08:22 Hamideh Jalali <jalali.hb_at_gmail.com> wrote:
>
>
> Dear FLUKA users
>
>
> We know the fluka results (fluence, dose, deposited energy and ...) are
> reported per primary particle, so we should multiply the fluka results by
> the number of primary particles to get the final value of our desired
> quantities. For example when we have an electron beam with a certain
> current, the number of primaries is determined by the current of beam
> (electron/second).
> In my case I have a number of photons which have different energies. In
> other word, in my FLUX.dat file there are two columns, first column is
> energy(E) and second is photon/s/energy(F). I used this file to program a
> source.f.
> Maybe there is a kind of misunderstanding with me about the calculation of
> the number of whole photons or primaries per second. I think, to get the
> whole number of photons I should multiply the second column in dat
> file(photon/sec/energy) by first column (energy). Then sum up all photon/s
> to find the final number of primaries per second. The fluka results should
> be multiplied by this number to get my desired quantity(dose equivalent
> rate in my problem).
> But by using this way, my final results are much more than expected
> values.
>
> There are some other methods to calculate the number of primaries:
> Sigma( (Ei+1 - Ei) * Fi )
>
> Sigma( (Ei + Ei+1) / 2) * Fi)
>
> Sigma ( (Ei+1 - Ei) *( Fi+1 + Fi))
>
> Sigma( (Ei + Ei+1) / 2) * (Fi + Fi+1))
>
> Could you please guide me which one is correct?
> I hope I could have explained clearly what I mean.
>
> Kind Regards
> Hamideh
>
>
>
>


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Received on Wed Aug 05 2015 - 17:54:40 CEST

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