  Several experimental collaborations worldwide intend to test sterile neutrino
models by measuring the disappearance of antineutrinos produced via isotope
decay at rest (IsoDAR). The most advanced of these proposals have very similar
setups, in which a proton beam strikes a target yielding neutrons which are
absorbed by a high isotopic purity 7Li converter, yielding 8Li whose resulting
decay yields the antineutrinos. In this note, we use FLUKA and GEANT4
simulations to investigate three proposed modifications of this standard
proposal. In the first, the 7Li is replaced with 7Li compounds including a
deuterium moderator. In the second, a gap is placed between the target and the
converter to reduce the neutron bounce-back. Finally, we consider cooling the
converter with liquid nitrogen. We find that these modifications can increase
the antineutrino yield by as much as 50 percent. The first also substantially
reduces the quantity of high purity 7Li which is needed.
