  This whitepaper reviews design options for the IsoDAR electron antineutrino
source. IsoDAR is designed to produce $2.6 \times 10^{22}$ electron
antineutrinos per year with an average energy of 6.4 MeV, using isotope
decay-at-rest. Aspects which must be balanced for cost-effectiveness include:
overall cost; rate and energy distribution of the electron antineutrino flux
and backgrounds; low technical risk; compactness; simplicity of underground
construction and operation; reliability; value to future neutrino physics
programs; and value to industry. We show that the baseline design outlined here
is the most cost effective.
