The Low Energy Neutral Imager (LENI)

To achieve breakthroughs in the areas of heliospheric and magnetospheric energetic neutral atom (ENA) imaging a new class of instruments is required. We present a high angular resolution ENA imager concept aimed at the suprathermal plasma populations with energies between 0.5 and 20 keV. This instrument is intended for high-spatial resolution ENA imaging of suprathermal plasmas. This technique could be used to understand the spatial and temporal structure of the heliospheric boundary recently revealed by Interstellar Boundary Explorer (IBEX) instrumentation and the Cassini Ion and Neutral Camera (INCA). The instrument is also well suited to characterize magnetospheric ENA emissions from low-altitude ENAs produced by precipitation of magnetospheric ions into the terrestrial upper atmosphere, or from energetic tails of ion outflow, or from the magnetosheath where solar wind protons are neutralized by charge exchange, or from the ring-current region. We present a new technique utilizing ultra-thin carbon foils, 2D collimation using a curved microchannel plate, and a novel electron optical design to produce high-angular resolution (≤2°) and high-sensitivity (≥ 10-3 cm2 sr/pixel) ENA imaging in the 0.5-20 keV energy range.