The output of ultraviolet converters typically used in satellite astronomy was monitored during irradiation with electrons from a sealed 90Sr source which approximated the peak flux in earth’s outer electron belt. The signal induced by irradiation was attributed to two mechanisms: (1) photoelectrons resulting from photons created in the MgF2 window and (2) the direct impact of electrons on the phosphor. For irradiation the at ~1 × 107 e/cm2 sec, these two effects produced signals which were, in order of magnitude, the same as those produced by an incident UV flux (254 nm) of 108 and 107 photons/cm2 sec, respectively. In addition, the induced signal was investigated as a function of electron energy by irradiating another converter with 0.4–1.8-MeV electrons from a Van de Graaff. These results suggest that the dominant contribution to the electron-induced signal is Cerenkov photon production in the MgF2 window.
© 1984 Optical Society of AmericaFull Article | PDF Article