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The following europium-activated phosphors were prepared: gadolinium oxide, gadolinium borate, gadolinium phosphate, lanthanum borate, and europium phosphate. The phosphors show an emission spectrum characteristic of the europium. From the excitation spectrum of some phosphors it is deduced that energy absorbed by gadolinium ions can be transferred to the europium ions. Most phosphors have a relatively high brightness at elevated temperatures. Gd203-Eu has a rather high luminous efficiency with cathode-ray excitation.