A PC104 Multiprocessor DSP System for Radiation Spectroscopy Applications

A multiprocessor DSP system hosted in a PC104 Windows CE industrial PC is presented. It is based on a master floating point Digital Signal Processor (DSP), a scalable number of slave DSPs and, special purpose trigger, pulse locator and data routing digital circuits. Although this architecture, as well as the data acquisition block, has been optimized to accommodate high throughput pulse rates in nuclear spectroscopy applications, its generality allows for many other signal processing and control applications to be implemented. Figure 1: γ-ray spectra of pottery [1] The function of a spectrometry system consists of converting the electrical-charge pulses originated at the output of the radiation detector into voltage pulses and, afterwards, obtaining their amplitude dis-tribution function as accurately as possible. This task has been accomplished, for decades, using a three stage almost all-analog system, schematically represented in figure 2: preamplifier, pulse shape amplifier, and the Multichannel Analyzer (MCA) that divides the amplitude space (generally as-sociated to energy) in a number of equally spaced intervals, usually referred to as channels. The number of the channels the system is capable to differentiate represents its energy resolution. 1