Abstract :
We study neutrino conversions in a recently envisaged source of high energy neutrinos {E > 10^6 GcV), i.e., in the vicinity of cosmological gamma-ray burst fireballs (GRB). We consider the effects of flavor and spin-flavor conversions and point out that, in both situations, a some what higher than estimated high energy tau neutrino flux from GRBs is expected in new km^2 surface area under water/ice neutrino telescopes.
