NuclearData
LAW=66 description omits distribution data
The LAW=66 write up in the ACE specifications do not mention the distribution data that is also produced by ACER and put there. See acefc.f90 (roughly around line 13400)
@whaeck and/or @HunterBelanger, do you have an example ACE file where we can see the output?
This ACE file uses the NBody for MT=16. It starts at index 40113 in the XSS block (C-style indexing). H2.txt
Interesting -- I never realized ACER spits out tabulated distributions for LAW=66 after the main parameters. The density function has an analytical form that can be easily sampled, so that data is superfluous (not used by MCNP, Serpent, or OpenMC).
It's actually not a problem since we have locators that point to specific pieces in the XSS array. If you look at the XSS array as a contiguous data array, then you might get into trouble if you do not know those distributions are there.
Understood. I'm just curious as to why it was put in there in the first place. I suppose MCNP might have used that data once upon a time?