Fast-slow coincidence systems with very high time resolution

The measuring of very short times recently became increasingly important. The authors describe their studies on the various parts of a timing system in an attempt to improve its parameters. The detector system, i.e. the transit time differences of the photomultipliers, the construction of the divider network, the various types of timing discriminators, the time-to-pulse height converters and the gating system were investigated. Two types of constant fraction discriminators are introduced: one for general timing applications, the other placed inside the detector head for positron lifetime measurements.