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Fine Resolution Epithermal Neutron Detector (FREND)

NSSDCA ID: 2016-017A-04

Mission Name: ExoMars 2016
Principal Investigator:Dr. Igor G. Mitrofanov


The Fine Resolution Epithermal Neutron Detector (FREND) is designed to map hydrogen on the martian surface down to a meter deep to reveal deposits of water ice near the surface. FREND will detect neutrons from the martian surface produced by natural cosmic ray bombardment. The scientific objectives for the experiment are to: perform high spatial resolution mapping of epithermal and fast neutron fluxes from the martian surface; monitor neutrons and charged particle fluxes over broad energy ranges during periods of quiet Sun and during solar particle events; provide maps of hydrogen concentration in martian soil at high spatial resolution; allow comparison of orbital and ground data as measured by FREND, the DAN instrument on MSL, and the Adron instrument on the ExoMars 2018 rover; and search for temporal changes in neutron fluxes related to seasonal water cycles and galactic cosmic ray variations.

FREND has three main components. Helium-3 counters detect epithermal neutrons with energies in the 0.4 eV to 500 keV range. A stylbene scintillator crystal detects neutrons with energies from 0.5 MeV to 10 MeV. A dosimeter module monitors the local radiation environment for any fluctuations that can impact the signals from the other two detectors. A collimation module is used to narrow the field of view to allow higher resolution.

Alternate Names

  • EXOMARS16/FineResolutionEpithermalNeutronDetector(FREND)

Funding Agency

  • European Space Agency (International)


  • Planetary Science: Atmospheres
  • Planetary Science: Geology and Geophysics

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Igor G. MitrofanovPrincipal InvestigatorInstitut Kosmicheskich Issledovaniya (IKI)
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