Certain types of fast pulse electronics, such as discriminators and coincidence units, are used almost universally in particle physics experiments. In this chapter we review some important features of these and other electronic equipment, strictly from the point of view of a user.

Fast pulse instrumentation

An important function of fast electronics in particle physics experiments is to decide if the spatial and temporal patterns of detector signals satisfy the requirements of the event trigger. Fast in this context generally means circuits capable of processing pulses at a 100-MHz repetition rate. Most detectors produce analog signals. Discriminators are used to convert these analog signals into standardized logic levels. Logic units are available that can perform the logical operations: AND, NAND, OR, NOR, and NOT. The input and output signal amplitudes of these devices correspond to two possible states: 0 to 1 (or T or F). The logic unit signals can be joined together so that the final output is only true when a predetermined pattern of input signals is present. This output pulse can be used to signal the occurrence of a physical event of interest.

The need for certain electronic devices such as discriminators and logic units in practically every experiment lead to the establishment of the NIM standard. Devices that satisfy the NIM requirements must be housed in standard sized modules with standard rear connectors. Up to 12 units can be plugged into a NIM bin.