  Neutron-induced fission of $^{237}$Np has been measured over a wide range of
incident neutron energies using a twin Frisch-gridded ionization chamber
(TFGIC) and a thin-backed $^{237}$Np target. These measurements were performed
at the Los Alamos Neutron Science Center - Weapons Neutron Research (LANSCE -
WNR) facility, which provides a collimated beam of neutrons with energies
ranging from 100s of keV to 100s of MeV. The data were analyzed using the
double-energy ($2E$) method, with mass-dependent corrections for prompt-fission
neutrons and pulse height defect. Pre- and post-neutron evaporation average
total kinetic energy ($\langle TKE\rangle$) values are reported for 54 incident
neutron energies in the energy range $0.20 \le E_n \le 100.0$ MeV and compared
to existing data and evaluations. Pre- and post-neutron evaporation mass yields
were extracted with a full width at half maximum (FWHM) resolution of 4u and
compared to existing data and evaluations. The present $\langle TKE\rangle$ and
mass yield data agree with previous results and also with statistical models of
$^{237}$Np$(n,f)$ at incident neutron energies between $E_n = 0.2 - 20.0$ MeV.
A flattening of the $\langle TKE\rangle$ data is observed (relative to the
prediction of the GEF model) above $E_n = 20.0$ MeV. However, the
interpretation of this discrepancy is unclear as the analysis method's neglect
of incomplete momentum transfer at high energies, as well as pre-equilibrium
pre-fission phenomena likely have a significant impact on the measurement at
such high incident neutron energies.
