Discriminators

The electronics system will need to be able to be operated remotely so that it can be fully integrated with the Exogam system which resides in the target area during an experiment. This is best achieved using constant fraction discriminator units that can be fully programmed via a control bus. Suitable units are available commercially and operate via CAMAC protocols. These units are made by the same manufacturer as the NIM-based amplifiers and are fully compatible. Suitable modules include the C-207, C-671, C-807 and C-808 programmable discriminators. Thus it will be necessary to set up a small CAMAC infrastructure to accommodate these CFD units, but this will then allow complete flexibility with the siting of the electronics. The discriminators will be used in the trigger definition electronics, which will be assembled using existing NIM modules. The discriminators will also be ganged together and used to produce a limited number of timing signals, such as the relative timing of a hit somewhere in the array compared to a hit in the zero-degree telescope.