The Energetic Particle Detector Instrument on ELFIN
Abstract
We present the design methodology, implementation, and data products of the Energetic Particle Detector (EPD) instrument on-board the Electron Losses and Fields Investigation (ELFIN) dual SmallSat mission. ELFIN was designed to study the time-evolution of energetic particle distributions in Earth's magnetosphere, having operated in polar Low Earth Orbit (LEO) from 2018 to 2022. Each satellite's instrument payload contained a pair of detector heads to sense differential-directional fluxes of 50 keV to ∼5 MeV electrons (EPDE), and 50 keV to ∼2 MeV atomic ions (EPDI), with an energy resolution better than 50% (ΔE/E<0.5). The satellites were spinning with a nominal period of 2.8 s in a plane containing Earth's background magnetic field, with particle counting intervals subdivided into 16 consecutive spin sectors. Each EPD was paired with a three-axis Fluxgate Magnetometer (FGM) sampled at 80 Hz for local pitch-angle determination. Each detector head operated on the principle of pulse-height analysis (PHA) in solid state media, collimated by a rectangular 22.5∘ field of view and entrance aperture. The EPDE contained a stack of 6 silicon detectors (0.7 cm total thickness) with 0.15 cm2 str geometric factor, with ion contamination mitigated by an aperture foil and digital coincidence logic. The EPDI contained a stack of 2 silicon detectors (0.1 cm total thickness) with 0.03 cm2 str geometric factor, with electron contamination mitigated by a magnetic broom stage and digital anti-coincidence logic. The total assembled mass, volume, and power required for the EPD detector heads and circuit boards were 939 g, 10×9.8×8.4 cm3, and 2.3 W, respectively. We describe each EPD design element alongside instrument data products and processing.
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BibTeX
@misc{wilkins2026energetic,
title = {{The Energetic Particle Detector Instrument on ELFIN}},
author = {Colin Wilkins and Ryan Caron and Ethan Tsai and Chris Shaffer and Patrick Cruce and Maxwell Chung and Andrei Runov and Jiang Liu and Drew Turner and Yuri Shprits and Wen Li and Michael Lawson and Emmanuel Masongsong and Cindy Russell and Eric Grimes and Jiashu Wu and Matthew Allen and Jessica Artinger and Alex Flemming and Brayden Hesford and Laura Iglesias and James King and Austin Norris and Carter Pedersen and Daniel Thomlinson and Wynne Turner and Vassilis Angelopoulos},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.18628},
eprint = {2610.18628},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.18628},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The Energetic Particle Detector Instrument on ELFIN
AU - Colin Wilkins
AU - Ryan Caron
AU - Ethan Tsai
AU - Chris Shaffer
AU - Patrick Cruce
AU - Maxwell Chung
AU - Andrei Runov
AU - Jiang Liu
AU - Drew Turner
AU - Yuri Shprits
AU - Wen Li
AU - Michael Lawson
AU - Emmanuel Masongsong
AU - Cindy Russell
AU - Eric Grimes
AU - Jiashu Wu
AU - Matthew Allen
AU - Jessica Artinger
AU - Alex Flemming
AU - Brayden Hesford
AU - Laura Iglesias
AU - James King
AU - Austin Norris
AU - Carter Pedersen
AU - Daniel Thomlinson
AU - Wynne Turner
AU - Vassilis Angelopoulos
PY - 2026
DA - 2026/10/13
PB - arXiv
DO - 10.48550/arxiv.2610.18628
UR - https://arxiv.org/abs/2610.18628
AB - We present the design methodology, implementation, and data products of the Energetic Particle Detector (EPD) instrument on-board the Electron Losses and Fields Investigation (ELFIN) dual SmallSat mission. ELFIN was designed to study the time-evolution of energetic particle distributions in Earth's magnetosphere, having operated in polar Low Earth Orbit (LEO) from 2018 to 2022. Each satellite's instrument payload contained a pair of detector heads to sense differential-directional fluxes of 50 keV to ∼5 MeV electrons (EPDE), and 50 keV to ∼2 MeV atomic ions (EPDI), with an energy resolution better than 50% (ΔE/E<0.5). The satellites were spinning with a nominal period of 2.8 s in a plane containing Earth's background magnetic field, with particle counting intervals subdivided into 16 consecutive spin sectors. Each EPD was paired with a three-axis Fluxgate Magnetometer (FGM) sampled at 80 Hz for local pitch-angle determination. Each detector head operated on the principle of pulse-height analysis (PHA) in solid state media, collimated by a rectangular 22.5^∘ field of view and entrance aperture. The EPDE contained a stack of 6 silicon detectors (0.7 cm total thickness) with 0.15 cm^2 str geometric factor, with ion contamination mitigated by an aperture foil and digital coincidence logic. The EPDI contained a stack of 2 silicon detectors (0.1 cm total thickness) with 0.03 cm^2 str geometric factor, with electron contamination mitigated by a magnetic broom stage and digital anti-coincidence logic. The total assembled mass, volume, and power required for the EPD detector heads and circuit boards were 939 g, 10×9.8×8.4 cm^3, and 2.3 W, respectively. We describe each EPD design element alongside instrument data products and processing.
ER -