A timing discriminator for channel plate electron multipliers

Abstract A constant fraction discriminator used with channel plate electron multipliers (CPEM) provides extremely good time resolution, yet it has a simple design and does not need delicate adjustment. The results obtained depend on the type of CPEM appartus which is used. For electron detection (β or conversion electrons) a resolution of 300 ps can be achieved for a system using two discriminators and two pairs of channel plate multipliers. For a similar double system this resolution becomes 65 ps for the detection of secondary electrons produced by the scattering of 252 Cf fission fragments in a carbon foil. The same type of discriminator can be used in systems employing fast photomultiplier tubes.