we've had..
01- Chadwick and Fermi
02- Nuetron Scattering & understanding of matter
03- Requirements for fission reaction
04- Features of Standard model of matter
05- Manhatten Project
06- Fission Requirements
07- De Broglie's proposal, and move from classical to quatum
So i dunno...they seem to have done everything. Fission reactions have been done too many times...maybe standard model of matter - hasn't been doen in a while.