  We study the high-energy equivalence between helicity 1/2 gravitinos and
goldstinos in order to calculate the production of gravitinos in time-dependent
scalar and gravitational backgrounds. We derive this equivalence for equations
of motion, paying attention to some subtleties, mainly due to external sources,
that are not present in the standard proofs. We also propose the Landau gauge
as a simplifying alternative to the usual gauge choices, both for practical
calculations and in the equivalence theorem proof.
