1. A ctually, due to the finite thickness of the detector, there are also upper energy limits for the detection of protons and electrons. The limit for protons is ∼50 MeV. The stopping power of protons with energy ≳50 MeV is small enough that they deposit less than the 0.5 MeV threshold energy in the active layer of the detector. This issue is important because the energy spectra of protons and electrons found in low earth orbits extend to energies of order 10 to 100 MeV.3
2. G. Ricker, J. Doty, S. Rappaport,et al., inNuclear Spectroscopy of Astrophysical Sources, edited by N. Gehrels and G. Share, AIP Conference Proceedings No. 170, AIP Press, N.Y., 407 (1988) and references therein.
3. E. G. Stassinopoulos inHigh-Energy Radiation Background in Space, edited by A. C. Rester, Jr. and J. I. Trombka, AIP Conference Proceedings No. 186, AIP Press, N.Y., 3 (1989).
4. In fact, compared to the proton channel, the electron channel with its higher reverse bias voltage can detect protons and electrons with higher energies. This is because the electron channel PIN diode has a thicker depletion layer and, thus, a higher upper energy limit.
5. T. Murakami, private communication, (1993).