Nobel Prize nominations were vetted by committees of five, one for each award.
Fermi initially intended to use polonium as a source of alpha particles, as Chadwick and Curie had done.
Values for the magnetic moment of the neutron were also determined by 1933 at and and 1934 in the from studies of the hyperfine structure of atomic spectra.
For Hahn, this necessarily involved asserting his claim of the discovery of fission for himself, for chemistry, and for Germany.
As a result, penetrating radiation was produced.