Institute of Geophysics and Planetary Physics, UCLA
Electron Loss and Field INvestigator - Lomonosov
UCLA IGPP ELFIN-Lomo project.

Energetic Particle Detector

The EPD draws from UCLA's particle detector experience with the OGO series and recent experience from the Solid State Telescope (SST) instruments launched aboard the THEMIS constellation in 2007.

Instrument Lead: V. Angelopoulos, vassilis@ucla.edu



The electron sensor contains a stack of eight 1000micrometers and two 500micrometers-thick solid-state Si detectors. An aluminized Lexan foil in front of the stack stops protons up to 500 keV and provides a light-tight environment.


The ion sensor contains two 1000micrometers-thick detectors and a samarium cobalt magnetic deflector to filter out low energy electrons. The front detector measures ion flux > 50keV. The 2nd detector implements anti-coincidence logic to disregard higher energy electrons that are not magnetically deflected.

Instrument Processing Unit

The IPU, positioned on top of the EPD sensors, provides command and data handling, compression, packetization, and redundant storage on non-voltatile flash memory for both the EPD and UCLA's PRM Triaxial Fluxgate Magnetometer.

Miniturized design

The mass, dimensions, power consumption, and data colume of the EPD are tailored for use aboardnanosatellites, including CubeSats.

Key Features:

  • Two sensors to differentiate electron and ion populations
  • Electron range: 50keV to 4Mev
  • Ion range: 50keV to 500keV
  • Aluminum and Tantalumshielding: Usable in radiation belt
  • Geometric Factors:
  • Electron: 0.04cm2sr
  • Ion: 0.003cm2sr
  • dE/E < 50%
  • The mass is < 1.5kg including 1.2cm-thick Al+Ta wall detector vault but no cover
  • Small module size 85 x 80 x 80 mm
  • Wide operating tempareture range ± 50 oC.
  • UCLA