FBK and Hamamatsu SiPMs Retain Functional Parameters After 20 krad TID and 1.12e11 p/cm² Proton Fluence

The arXiv study exposed 1×1 to 6×6 mm² devices to Co-60 gamma rays at ESA/ESTEC and 100 MeV protons at PSI. Dark current rose predictably from displacement damage under protons far more than from ionizing dose, yet gain and breakdown voltage stayed within mission tolerances. Indirect extraction of dark-count rate from I-V curves showed both vendors' technologies remain operational in typical LEO trapped-particle environments.

Prior CubeSat missions using untested SiPMs reported unexpected noise spikes after six months; the controlled fluence levels here map directly onto 2–5 year polar orbits, closing that gap. The work also quantifies that NIEL-induced defects dominate over TID effects, guiding shielding mass budgets for future Earth-observation spectrometers.

Designers of the upcoming ESA Scout missions can now adopt these exact part numbers without additional qualification campaigns. Remaining open questions center on combined thermal-vacuum cycling with radiation, which the present electrical-only protocol omitted.

Follow-on beam tests at higher energies and on-orbit dosimeter data from a 2025 technology demonstrator will tighten the lifetime models before constellation-scale procurement.