A new sixteen channel leading-edge discriminator for time-of-flight experiments at COSY

A novel 16-channel leading-edge discriminator (LED) is described. The module was designed for use with fast plastic scintillators at the time-of-flight spectrometer currently being built at Julich. In view of the large number of discriminator channels required for this experiment, the module price has been considered during the development. Therefore, the discriminator is placed in a modified Curocard system instead of using a standardized bus system, like CAMAC. Basically, the LED consists of the RAL 10, a commercially available integrated circuit containing all the building blocks needed to realize a LED, as well as a constant-fraction discriminator (CFD). For this reason it is possible to use the module as a CFD at a minimum of additional hardware. In LED mode a time walk of less than 800 ps in an amplitude range of -20 mV to -2 V has been achieved for signal rise times between 1 ns and 5 ns. Circuit diagrams and typical measured data are presented