What means that error ?
***** Neutron Xsec: ****
**** Group limits, average energies, velocities and momenta start at location 10358771, end at location 10360938 (I*4 addr.) *****
*** Recoil proton production activated for Xsec mat. # 1 ***
**** Low energy neutron xsec not found for some media 15 16 ****
Here is definition of COPPER1
MATERIAL 29.0 65.0 8.65 32.0 0.0COPPER1
Please, have a look at this thread where the same problem has already been addressed.
I added the next LOW-MAT card and error disappeared. But I can’t understand what means numbers of WHAT3 and WHAT4. Can you explain please ?
MATERIAL 29.0 65.0 8.65 32.0 0.0COPPER65
LOW-MAT COPPER65 29 -2 296 0.0 0.0COPPER
I suppose you’re talking about the LOW-MAT card.
Have a look at manual page 10.4.1.2 Available cross sections
I copy here a snippet containing copper, which is what you are interested into.
You can see that for copper (as for most of the other materials) there is more than one cross section value set available, specifically 8.
Cu Natural Copper 296K ENDF/B-VIR8 Y COPPER 29 -2 296 Y
Cu Natural Copper 87K ENDF/B-VIR8 Y COPPER 29 -2 87 Y
Cu Natural Copper 4K ENDF/B-VIR8 Y COPPER 29 -2 4 Y
Cu Natural Copper 430K ENDF/B-VIR8 Y COPPER 29 -2 430 Y
Cu Natural Copper SelfShielded 296K ENDF/B-VIR8 Y COPPER 29 -4 296 Y
Cu Natural Copper SelfShielded 87K ENDF/B-VIR8 Y COPPER 29 -4 87 Y
Cu Natural Copper SelfShielded 4K ENDF/B-VIR8 Y COPPER 29 -4 4 Y
Cu Natural Copper SelfShielded 430K ENDF/B-VIR8 Y COPPER 29 -4 430 Y
In this case they corresponds to different temperatures and to a self-shielding copper. The different cross section value set are identified by 3 “identifier” (e.g. 29, -2, 296 for the first; 29, -2, 87 for the second, etc.).
If you don’t provide any identifier, the first entry of each material will be selected.
What means “self-shelded” ? What’s the difference between self-shelded and the simple one ?