Hello! My input is declaring an error 12, related to the COMPOUND card, with the elements of the nucleus and cytoplasm of the cell, what could it be?
thank you very much!!
celula.flair (3.1 KB)

Dear Victoria,

If you look in the long output (celula_01001.out) you can see that the low energy neutron cross sections for several materials are not found. You have to introduce the LOW-MAT cards for those materials.

… or you can name the single-element materials as in the low energy neutron library, as already pointed out.
Please note that this is exactly the same problem previously answered, and Error 12 does not mean anything specific, you should look at the output (and log/err) file as recalled by @Mihaela_Parvu .