I am trying to score both the neutron yield (total and energy spectra) inside a region and the neutron current (total and energy spectra) through the region’s surface. In order to do so I’ve used a USRYIELD and a USRBDX card for each respective scoring.
The results I am getting are rather strange, since the total yield is smaller than the total current, which leads me to believe I might be setting up the scoring wrong. For the neutron current I get: 5.1460001E-03 part/primary, while for the yield I get: 4.0958522E-04 part/primary. The same behaciour where the yield is smaller than the current is seen in the energy spectra:
Your input is not compatible with the FLUKA versions released by CERN. Support is only provided here for this version.
If you still have issues even with this FLUKA release, please let us know.
You are right, I did send the other version’s input file and results. Nevertheless, when running it with the CERN released version, I encounter the same issue (although slightly different results).
Here is the corresponding results and input file:
Total neutron current = 5.2700001E-03 part/primary
I suspect I might not be correctly taking into account the normalization respect to the emission polar angle… the yield is given in [particles/GeVsrprimary] is that right?
In the case of polar angle quantities (|ie| or |ia| = 14, 15, 17, 24, 25, 37) the differential yield is always referred to solid angle in steradian, although input is specified in radian or degrees.
Or from the sum.lis output file:
2nd variable (x2) differential is a solid angle one
you see that the USRYIELD result is differential in the solid angle in your case. So if you multiply it with 4*\pi you get the same result as the neutron current (within the statistical error).
If you are not interested in the second quantity of the USRYIELD scoring, you can choose Particle charge and set it to [-0.5..0.5], thus setting the normalization factor of the second quantity to 1.
