Papal cross his office. It was often merely an artistic device, as use of a staff or crosier was not part of the traditional papal insignia. However, at least one staff surmounted with a papal cross does exist. Symbolism connected with the papal powers have been attached to the three crossbars, similar to the symbolism attached to the three bands on the papal tiara. Papal cross The papal cross is a Christian cross, which serves as an emblem for the office of the Pope in ecclesiastical heraldry. It is depicted as a staff with three horizontal bars near the top, in diminishing
Neutron cross section of the order of "π r" or roughly 10 cm (thus justifying the definition of the barn). However, if measured experimentally ( "σ" = "R" / ("Φ N") ), the experimental cross sections vary enormously. As an example, for slow neutrons absorbed by the (n, γ) reaction the cross section in some cases (xenon-135) is as much as 2,650,000 barns, while the cross sections for transmutations by gamma-ray absorption are in the neighborhood of 0.001 barn (See here for more example of cross sections). The "nuclear cross section" is consequently a purely conceptual quantity representing how big the nucleus should