Suppose that an element has a microscopic absorption cross section of 100,000 barns. For neutrons in the thermal energy range, is this considered to be a small, a medium, or a large cross section by...

Suppose that an element has a microscopic absorption cross section of 100,000 barns. For neutrons in the thermal energy range, is this considered to be a small, a medium, or a large cross section by nuclear standards? Name at least one element that has an isotope with an absorption cross section that is approximately this large