  We analyse how the spatial localisation properties of pairing correlations
are changing in a major neutron shell of heavy nuclei. It is shown that the
radial distribution of the pairing density depends strongly on whether the
chemical potential is close to a low or a high angular momentum level and has
very little sensitivity to whether the pairing force acts in the surface or in
the bulk. The averaged pairing density over one major shell is however rather
flat, practically independent of the pairing force. Hartree-Fock-Bogoliubov
calculations for the isotopic chain $^{100-132}$Sn are presented for
demonstration purposes.
