PROGRESS IN MULTIELEMENT SILICON DETECTORS FOR SYNCHROTRON XRF APPLICATIONS

Multi-element silicon strip detectors, in conjunction with integrated circuit pulse-processing electronics, offer an attractive alternative to conventional lithium-drifted silicon and high purity germanium dete ctors for high count rate, low noise synchrotron x-ray fluorescence ap plications. We have been developing these types of detectors specifica lly for low noise synchrotron applications, such as extended x-ray abs orption fine structure spectroscopy, microprobe x-ray fluorescence and total reflection x-ray fluorescence. The current version of the 192-e lement detector and integrated circuit preamplifier, cooled to -25 deg rees C with a single-stage thermoelectric cooler, achieves an energy r esolution of <200 eV full width of half maximum (FWHM) per channel (at 5.9 keV, 2 mu s peaking time), and each detector element is designed to handle similar to 20 Id-It count rate. The detector system will soo n be completed to 64 channels using new application specific integrate d circuit (ASIC) amplifier chips, new CAMAC (Computer Automated Measur ement and Control standard) analog-to-digital converters recently deve loped at Lawrence Berkeley National Laboratory (LBNL), CAMAC histogram ming modules, and Macintosh-based data acquisition software. We report on the characteristics of this detector system, and the work in progr ess towards the next generation system.