Problem with neutron flux spectrum in OpenMC

[DinaEl]

Hello everyone

I am working on an OpenMC simulation and trying to plot the neutron flux spectrum.
However, the spectrum I obtain is very irregular and does not match the expected shape.
I have already increased the number of particles, but the issue persists.
Could the problem be related to the energy bins, source definition, or flux normalization?
Any guidance would be appreciated
Thanks

[wahidluthfi]

Hi Dina, have you checked this notebook of neutron flux spectrum? Most of the time, I am showing spectrum with the unit of divided flux value to the width of the energy bin. In that notebook, the process was done with flux_mean/np.diff(energies), but you can also divide that by lethargy if you want.
Besides, I am usually use a linear y axis since I have normalizing the mean value before. Hope that could help you.

flux-spectrum.ipynb

[DinaEl]

@wahidluthfi

Hi Dina, have you checked this notebook of neutron flux spectrum? Most of the time, I am showing spectrum with the unit of divided flux value to the width of the energy bin. In that notebook, the process was done with flux_mean/np.diff(energies), but you can also divide that by lethargy if you want.
Besides, I am usually use a linear y axis since I have normalizing the mean value before. Hope that could help you.

Thank you for the explanation. I understand that the spectrum is normalized by the bin width (energy or lethargy). I will implement both approaches and check the difference