Page "Photomultiplier" Paragraph 16
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Also in 1936, a much improved photocathode, Cs < sub > 3 </ sub > Sb ( caesium-antimony ), was reported by P. Görlich.
The caesium-antimony photocathode had a dramatically improved quantum efficiency of 12 % at 400 nm, and was used in the first commercially successful photomultipliers manufactured by RCA ( i. e., the 931-type ) both as a photocathode and as a secondary-emitting material for the dynodes.
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