A Low-Cost General Purpose Spectral Display Unit Using an IBM PC

Many physics experiments require acquisition and analysis of spectral data. Commercial minicomputer-based multichannel analyzers collect detected counts at various energies, create a histogram of the counts in memory, and display the resultant spectra. They acquire data and provide the user-to-display interface. The system discussed separates functions into the three modular components of data acquisition, storage, and display. This decoupling of functions allows the experimenter to use any number of detectors for data collection before forwarding up to 64 spectra to the display unit, thereby increasing data throughput over that available with commercial systems. An IBM PC was chosen for the low-cost, general purpose display unit. Up to four spectra may be displayed simultaneously in different colors. The histogram saves 1024 channels per detector, 640 of which may be distinctly displayed per spectra. The IEEE-488 standard provides the data path between the IBM PC and the data collection unit. Data is sent to the PC under interrupt control, using directsmemory access. Display manipulations available via keyboard are also discussed.