Hi all
I was trying to create a plot of tungsten n,total and n,gamma and noticed that n,gamma is higher than n,total in the low energy range (screen shot attached).
I did a similar plot using just the isotopes and noticed that the n,total is higher as I was expecting (screen shot attached).
I was using the calculate_cexs function to find the cross sections but perhaps I have don this incorrectly (script attached)
Perhaps this is my misunderstanding but shouldn’t n,total always be higher and shouldn’t these two graphs have the same general shape.
Any insight much appreciated
best
Jon
plot_tungsten_material_and_isotope.py (2.2 KB)
Hi Jon,
I’ve actually seen this as well and meant to post an issue, but got distracted. I believe the total is actually returning the elastic scattering cross section (MT=2). See if that is what’s happening in your case.
Cheers,
Ethan
Interesting, I checked and you are right this is also happening in this case, the ‘total’ returns the same result as the elastic scattering cross section (MT 2). I wonder if this has more consequences than just a slight strange plots. I shall have a quick look around the source code.
Thanks for your help
best
Jon
Just following up on this post – there is now an issue on the OpenMC repo tracking this:
https://github.com/openmc-dev/openmc/issues/1561
