Setting material as natural lead or specific lead isotope

hello dear fluka expert
I want to compare application of pb-206 with pb-nat in bonner detector. I applied pb-206 in the material card, but the input didnt run. and why fluka doesnt have the low-mat card for pb-206?
the best regards

hello dear
I am simulating the application of pb-208 and pb-nat for bonner detector.
but the result werer it error?
the input file is attached.
1 (1).inp (1.9 KB)
the best regards.

Use the neutron point-wise transport (see the manual), with no LOW-MAT card and an empty LOW-PWXS card.

Thank you for your answer.