Energy discretization and data normalization in DETECT card

Scoring
1

Dear Fluka experts,

I’m having a couple of issues with the scoring card DETECT.
My goal is the following: I would like to reproduce the gamma spectrum of a Eu152 point source, simulated via the “source.f” subroutine, and compare it with the one measured via an HPGe detector with an energy axis subdivided in about 0.24 keV/channel.
The main objective is then to compute the peaks area for an absorption analysis.

  1. Before knowing how to manually change the number of channels, I’ve used 8 DETECT cards in the same region spanning different energy ranges, in such a way to obtain the correct energy discretization; if it is not the problem cause I would like to stick with this approach, mainly due to convenience reason.
    When I process the data from the *_17_tab.lis file, using a MatLab function, I run into a problem with energies greater than 1 MeV, since the data are rounded with a too low number of significative digits to appreciate the energy variation, even if I use the double precision notation. More specifically, the file actually recognizes different bins but gives the same begin-end energies for groups of two or three neighbouring bins, resulting in a stairs-like energy axis increase.
    Is there any way to increase such number of digits?

The other question I have is instead related to the content of “tab.lis” file interpretation:
2) Considering the result that represents “the fraction of gamma depositing their energy inside the detector volume”, are such values normalized on the energy bin?
I understood that if the field “trigger” is left blank during the DETECT card declaration, such fraction is relative to the total primary photons number, so after evaluating the integral of the entire simulated spectrum and known the actual geometrical efficiency equal to 0.2%, the result was a little bit confusing considering both the options (normalised and non-normalised) and left me this doubt.

Thanks in advance!
Best regards
Michele

2

Dear Michele,

  1. I updated the detsuw.f post processing tool for the DETECT card. detsuw.f (5.9 KB)

    You need to replace the existing one in the following the directory /usr/local/fluka/src/tools.
    Then you need to compile it. The easiest way is to use the following command in /usr/local/fluka/src:

    sudo make clean && sudo make

    With this change the energy bin boundaries are written with 1 eV precision.

  2. The results of the DETECT scoring is only normalized by the number primaries (weight). However, since you are using a source routine, further normalization maybe needed to get the correct number of photons per decay.

    Also please keep in mind:

Cheers,
David

3

Thank you very much!!