A Software System for Data Acquisition in Nuclear Physics Experiments Using CAMAC

An event-oriented, modular software system for data acquisition in nuclear physics experiments has been implemented on PDP-11 computers under the RSX-11D operating system. The system is designed to support high-speed data acquisition in a broad variety of nuclear physics experiments having multiple event types and using CAMAC instrumentation as the experimental interface. The system provides a simple, problem-oriented language for the specification of CAMAC operations to acquire data from each class of event. It provides automatic bufferinq of experimental data from the CAMAC hardware and recording on magnetic tape. Certain common utility functions are provided, especially histogram entries and plotting on on-line displays, along with associated operator control functions. The experimenter specializes the system to his needs by writing FORTRAN subroutines which specify necessary on-line analysis of data and control histogram entry. The software depends on a special event-trigger module which was designed in conjunction with the software and is used to identify the various different classes of events, to facilitate manual control and testing of an experiment, and to facilitate comnmunication between different software modules in the system.