Performance Tests of a Scalable Multi-Detector Digital Spectrometer with Eight Channels

(1) Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, Texas 76203, USA
(2) Faculty of Mathematics and Computer Science, University of Leipzig, PF 100920, 04009 Leipzig, Germany

Digital pulse processing in ion beam analysis is still not very common. Commercially available systems are not yet versatile enough to suite the needs for flexible and multi-modal ion beam analytical setups. Therefore, lab-specific solutions are under development with more or less success. If ion beam scanning is required, solutions become even more complicated since synchronization between the data streams from the detector channels and the scan control is necessary. We present the design and the results of performance tests of our scalable multi-detector digital spectrometer. It is currently configured with two digitizers (ADQ412), each with four-channel, 12 bit, and 1 GHz sampling frequency. The scan control module is a two-channel 16-bit, 50-MHz sampling frequency digital to analog converter. The digitizer and scan modules are synchronized via the chassis backplane PCI bus. Digital pulse processing of the detector signals is realized onboard the digitizer cards using a field programmable gate array.  The system is designed to handle data rates of up to 1 MHz per channel.