Cause of the ELFIN-B E5 Detector Failure

Determine the particular cause of the E5 detector failure on Flight Model 2 (ELFIN-B), which produced a highly irregular, large-amplitude voltage waveform unrelated to any identified system frequency.

Background

The E5 detector on the second flight-model instrument, flown on ELFIN-B, failed after integration and was disabled for the entire mission. The failure affected only the highest-energy electron measurements, above approximately 3 MeV, and simulations indicated that the mission data were not noticeably degraded relative to ELFIN-A because the instrument sensitivity was already low in that range. The paper reports that the physical cause of the failure was not identified, leaving the origin of the anomalous waveform unresolved.

References

The particular cause is unknown, but resulted in a highly irregular, large-amplitude voltage waveform that did not correspond to any frequency in the system.

— The Energetic Particle Detector Instrument on ELFIN  (2610.18628 - Wilkins et al., 13 Oct 2026) in Section 5.1, subsection “Detector selection”