Data acquisition and monitoring system for the UHE gamma ray experiment at Kolar Gold Fields

A computerised on-line data acquisition system has been implemented to acquire data and monitor all the detectors in an extensive air shower experiment at Kolar Gold Fields, India, designed to search for point sources of Ultra High Energy gamma rays. It is based on the LSI-11 microcomputer, which has a powerful instruction set and a daisy chained vectored interrupt facility. Two personal computers are linked with LSI-11 through a 16-bit communication bus, to transfer data for a quick analysis. While the system performs this function in the background, it can be interrupted, at different priority levels, by several foreground functions, such as event data acquisition, detector monitoring, etc. The hardware and software features of the data acquisition system are described in detail. (orig.)