2.2.2 spase://SMWG/Instrument/MarsExpress/ASPERA3/NPI Mars Express ASPERA-3 Neutral Particle Imager 2019-05-05T12:34:56Z The Neutral Particle Imager (NPI) of the ASPERA-3 package flown on Mars Express provides measurements of the integral ENA flux with no mass and energy resolution but with 5 deg x 11 deg angular resolution. The intrinsic field of view is 9 deg x 344 deg. The sensor utilizes a graphite surface to suppress the UV background. ENAs incident on the surface at a grazing angle of 20 deg are reflected and/or cause ion sputtering. An MCP stack detects the reflected particles and sputtered fragments with a discrete anode. spase://SMWG/Person/Rickard.Lundin PrincipalInvestigator PDS ASPERA web page http://pds-geosciences.wustl.edu/missions/mars_express/aspera.htm NeutralAtomImager ASPERA3_NPI spase://SMWG/Observatory/MarsExpress