Photocathodes used in photomultiplier tubes for scintillation counters-characteristics and effect on performance

In recent months a variation of the caesium antimony cathode has been developed with a quantum efficiency up to 30%. The characteristics of this 'super' S-11 cathode are compared with the caesium potassium bialkali cathode, the trialkali cathode and other variants of the caesium antimony cathode. The parameters dealt with are quantum efficiency, spectral response, dark current at various temperatures and the resolution for gamma rays of both low and high energy.