High speed data acquisition system for large area proportional counters

Abstract

A modular, UNIX/X-Windows/Sun SPARC-based data acquisition and analysis system provides NASA X-Ray Timing Explorer (XTE) Proportional Counter Array (PCA) scientists with near real-time access to space flight instrument ground test data. This system processes data directly from five large-area, xenon-filled low-background collimated proportional counters at rates up to 2 MB/s in a networked, real-time environment. Science events are sent serially from the proportional counter flight electronics and multiplexed on a custom-designed data acquisition board. Each event is tagged with a time stamp of 1 /spl mu/s resolution and a detector identifier. A commercial Direct Memory Access (DMA) board interfaces directly to the data acquisition board allowing asynchronous transfer of buffered data to software residing on a high performance workstation. A windows-based interface provides an operator with acquisition command and control functions to capture data through the DMA board. Data is collected, buffered, and archived to magnetic disk. Histogramming and statistical functions are provided by the software enabling real-time pulse height spectroscopy, rate analysis, and spectral analysis. >