A DUAL-PARAMETER MULTICHANNEL ANALYZER USING A PERSONAL-COMPUTER

The design of a practical system for measuring two-parameter signals is reported. To obtain constantly changing energy spectra of nuclear reactor assemblies due to repeated insertion of pulsed neutron sources, the simultaneous acquisition of time and energy data is needed. A computer-based dual-parameter multichannel pulse-height analyzer was developed. The analyzer uses a personal computer, two analog-to-digital converters (ADCs), and a parallel interface board for handling these signals. The system showed excellent performance characteristics with a minimum data-processing time of about 14 μ s a maximum conversion gain of 218 channels (for example, 512 × 512 ch) a count capacity of 232-1/ch (216-1/ch at 512 × 512 ch) and the time required for graphic display of approximately 3 s/216 dots (contour display) or about 0.1 s/(216/16) dots (isometric display). Large data arrays were handled dynamically with a segment register. The data-processing speed was improved by transferring the data from the ADC to the central processing unit in 16-b words and simultaneously reading the status flag and the data. The graphic display process was speeded up by writing the data bit corresponding to the locations directly into the graphic video random access memory. The system is simple to operate, and because the memory size and coincidence resolution time can be changed by software operations, it is highly flexible.