Terbium activated silicate luminescent glasses for use in converting x-ray radiation into visible radiation

A method of converting x-ray radiation into radiation in the visible spectrum comprising the steps of:

• a. positioning in said x-ray radiation field a luminescent terbium-activated, silicate glass exhibiting strong visible luminescence, low phosphorescence and low background buildup when exposed to x-ray radiation in the range of 5 KeV to 16 MeV and consisting essentially, by weight on the oxide basis, of about 3-25% R.sub.2 O wherein R.sub.2 O consists of 0-5% Li.sub.2 O, 0-25% Na.sub.2 O, 0-25% K.sub.2 O, 0-25% Rb.sub.2 O, and 0-25% Cs.sub.2 O;
• 5-55% RO wherein RO consists of 0-20% MgO, 0-30% CaO, 0-45% SrO and 0-55% BaO;
• 35-70% SiO.sub.2 ;
• 0-20% R.sub.2 O.sub.3 wherein R.sub.2 O.sub.3 consists of 0-20% La.sub.2 O.sub.3 and 0-15% Y.sub.2 O.sub.3 ;
• 0.1-2% of at least one oxide selected from the group consisting of cerium oxide and europium oxide;
• 5-20% Tb.sub.2 O.sub.3 ;
• and 1-15% Gd.sub.2 O.sub.3 ;
• and
• b. irradiating said glass with said x-ray radiation, thereby to convert said x-ray radiation into said visible radiation.