Dear Fluka users,
I want to plot neutron spectra for different primary proton energies impinging on a simple and cylindrical tantalum target. However, when I plot it, some problems arise.
I know that Usrtrack will deliver me the differential fluence dÖ/dE with the unit neutrons/cm^2*GeV^-1*primary in the third column of the tab.lis file, which was obtained by processing the corresponding fort files by means of the ustsuw command (please find that file enclosed). Im not totally sure if a semi- or double-log plot would be best suited here. The semilog plot would show a steeper peak, the double log plot would however also show the variation of the fluence at very small and high energies with very small fluences. If I want to plot the data in the form of a double-log plot I have to process the zero values in order to avoid gaps in between. So far I decided to delete these values, this however leads to a higher bin width at some points and an unequal bin width in general then. When the bin width increases, one could obtain a somewhat misleading impression I think since the plot then pretends at some points that there is a fluence but indeed it is not.
Another common option to plot my data would be to multiply all the y-values by the energy bin width, so that I get neutrons/cm^2*primary on the y-axis. However, I have realized that this will usually always lead to irritating results since the bin width from 1E-14 GeV up to 20 MeV (which is fixed due to the multi-group transport of neutrons in FLUKA) differs from the bin width after 20 MeV, where the program considers the chosen bin width taken by the user. Consequently, an irritating "jump" up or down after 20 MeV would be visibile.
Apart from that I know that I could move from a stairstep graph to a common line graph if I take the middle of each bin as my x-value.
I would be very thankful if you could help me and tell me what would be the best way to plot the data correctly.
With best regards,
Niklas
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Received on Sat Mar 14 2020 - 18:32:08 CET