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Emission and excitation spectra of CaF2, SrF2, BaF2 doped with Nd3+, Sm3+, Ho3+, Er3+, Tm3+ excited by vacuum ultraviolet photons or by x-rays were studied. Decay times of the Nd3+ emission near 180 nm at 7 K were 17.7, 15.3, 12.3 ns in CaF2 , SrF2 , BaF2 respectively. 4fn-1 5d1-4fn luminescence bands were found at 170-200 nm for Sm3+ ions and at 140-190 nm for Ho3+. No excitation of 5d-4f emission of Nd3+ and Tm3+ was observed in the region of band-to-band transitions below 127 nm (BaF2), 120 nm (SrF2) and 115 nm (CaF2). Emission spectra of Nd and Er doped alkaline-earth fluoride crystals under x-ray excitation were studied with concentration of impurity from 0.01 to 10 molar %. For the Nd3+ and Er3+ 5d-4f emissions in SrF2 the light yields were estimated as 30-40 ph/Mev.