Fission product mass yields from fast neutron-induced fission of $^{237}\mathrm{Np}$

$^{237}\mathrm{Np}$ is produced in significant quantities in the nuclear fuel cycle. Its presence in spent reactor fuel coupled with its $\sim 2\times10^6$ year half life make a complete and precise understanding of its nature critical to reactor design, particularly that of fast reactors. Although the fission cross section of $^{237}\mathrm{Np}$ has been measured for a wide range of incident neutron energies, little total kinetic energy (TKE) data exists for $^{237}\mathrm{Np}(n,f)$, and there are no TKE nor mass yield data for incident neutron energies above $E_n = 5.55$MeV. Measurements of the TKE of correlated fission fragments from $^{237}\mathrm{Np}(n,f)$ at incident neutron energies from $E_n = 0.5 - 40$MeV have been performed at the Los Alamos Neutron Science Center Weapons Neutron Research facility using using a twin Frisch-gridded ionization chamber and a thin-backed $^{237}\mathrm{Np}$ target. Fission mass yields have been extracted from the data using the double energy method. In this talk, experimental methods, analysis techniques and preliminary results will be discussed.