Spectral response of anth"y-caesium photocathodes

Measurements have been made of the relative photoileclric quantum eficiency ?(A) of SbCs3 cathodes of M ith Pyrex and quartz windows, from ~=200-650 mp. ?(A) depends on the window transinittame W(h), the cathode absorbance A(h, d) , the absolute photoelectric quantum efiiciency Qo(h) and the p/1otoelectron escape probability f (A, d). Comparison Irith other data has allowed the separation of these factors, yielding inter alia the absorption spectrum of SbCs3 down to h = 220 mp, and the absolute photoelectric threshold curre Qo(h) plotted against h. The optimum thickness for a thin cathode is d = 200 A. Errors in other published data are noted, and methods of increasing ?(A) and of improving scintillation detectors are discussed. -~