Authors: Hafijul Islam (University of New Hampshire) Fatemeh Rahmanifard (University of New Hampshire) Nathan Schwadron (University of New Hampshire) Ebarhard Mobius (University of New Hampshire)

The IBEX-Lo sensor on the Interstellar Boundary Explorer (IBEX) mission observes primary and secondary interstellar helium in the four lowest energy steps. Observations of these He populations have been systematically analyzed and compared to simulations using the analytic full integration of neutrals model (aFINM). An unexpected difference for secondary helium is observed between the simulations and observations during solar maxima of Solar Cycle 24. We analyze plausible causes for this deviation and their implication for the study of direct detection of the interstellar neutral atoms inside the heliosphere.