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Proton-induced absorption over the 280-700-nm region and growth of that coloring with increasing dosage of proton radiation were determined for three Schott glasses used as focusing elements in the International Ultraviolet Explorer. It was found that the absorption spectra for each glass can be fitted with three Gaussian shaped bands in the near UV-visible range, while a fourth Gaussian characterizes the absorption edge. For doses up to 10(7) rads, the dependence of the induced absorption alpha on total dose Phi is accurately described by the saturating exponential function alpha(lambda,Phi) = alpha(s)[1 - exp(-bPhi)], where alpha(s) and b are constants dependent on the wavelength and glass type. The proton irradiation results were then compared to the effects of electron irradiation on those same three types of glass. For any one glass, it was determined that electrons and protons produced absorption bands with peaks at the same energies but with different saturation levels. For the glasses and wavelength region investigated, proton irradiation induced higher absorption saturation levels alpha(s) in the longer wavelengths, while electron irradiation induced greater absorption in the shorter wavelengths.

Proton-induced degradation of vacuum ultraviolet (VUV) transmittance of LiF and MgF(2) was measured for 85- and 600-MeV protons for a fluence up to 2.8 x 10(13)p/cm(2). Transmittances were measured from 105 to 210 nm. When the irradiation level for a given material is expressed in terms of absorbed energy per unit of volume of crystal, 85- and 600-MeV protons produce the same degradation. MgF(2) is substantially more radiation resistant than LiF in the VUV. Irradiation of LiF with 1.8 x 10(13)p/cm(2) at 85 MeV changed the transmittance of the hydrogen Lyman-alpha line at 121.6 nm from 55 to 23%. The corresponding change for MgF(2) was from 52 to 42% for 2.8 x 10(13)p/cm(2).

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