3200 ANGSTROM PHOSPHOR

Alterations and improvements in the instrumentation and techniques for phosphor efficiency and life measurements were completed. The efficiency of Zn2SiO4:TiO2, settled without ball-milling, was measured and found to be as high as 7%. Several methods for breaking up clusters were explored. Of these, dry rolling proved successful producing fine particle size, without impairing the original efficiency even when carried out for as long as 72 hours. By comparison P-16 screens gave initial efficiencies of 3.9 and 3.0%. The (Ba,Zn)2Si4O10:Pb system was investigated in detail, and a Ba/Zn ratio of 1.3/0.7 was found to give an efficient phosphor with a highly satisfactory match to the desired emission spectrum. The (Sr,Ca,Zn)3Si2O7:Pb system was studied extensively and the effects of variations in the mole fractions of the three cations were determined. It was found that Sr-rich compositions with Zn mole fractions near one-third give the shortest peak wavelengths (3300-3350A) and the most efficient phosphors. Samples of CaSiO3:Tl and SrSiO3:Tl were prepared; these proved to be very inefficient phosphors. (Author)