• De Geronimo, Gianluigi
• Paterson, David
• Kuczewski, Tony
• Hough, Rob
• Cleverley, James
• Lintern, Mel
• De Jonge, Martin
• Howard, Daryl
• Davey, Peter
• Myers, Damian
• Siddons, Pete
• Dunn, Paul
• Moorhead, Gareth
• Laird, Jamie
• Jensen, Murray
• Ryan, Chris

Abstract

Construction of the Maia annular 384 detector array [1,2] for the X-ray Fluorescence Microscopy (XFM) beamline at the Australian Synchrotron has been completed and tests are underway. Meanwhile, a 96 detector prototype array has been in use at XFM for a wide range of applications and plans are developing to install a Maia 384 detector in the CSIRO Nuclear Microprobe. This paper provides an outline of the Maia concept, reports on developments in methods for real-time processing of event data, corrections to the fundamental parameter approach to quantification and spectral deconvolution method to deal with large detector solid-angle (~1.2 sr) and illustrates Maia performance using applications involving natural samples.Developed by CSIRO and Brookhaven National Laboratory, Maia combines a 96 or 384 silicon detector array and a high speed, FPGA based, pipelined, parallel processor that enables real-time processing of each detected X-ray event tagged by detector number and XY position in the image scan. Using an embedded spectral deconvolution algorithm based on the Dynamic Analysis (DA) method [3], the processor accumulates deconvoluted element images in real-time. The real-time processing pipeline includes: (i) event correction for linearization, (ii) gain trimming to match spectra from individual detector channels, (iii) pile-up rejection, (iv) DA image accumulation, (v) monitor spectra accumulation, (vi) intelligent sub-sampling to conserve disk space and (vii) logging of raw and accumulated data to disk. The detector systems may drive the XY sample stage directly, or read back stage encoder or laser interferometer values to sample position and focusing zone-plate location.Real-time event processing enables transit times per pixel as short as 50 µs and scanning up to ~10000 lines to collect high definition SXRF images up to ~100M pixels [4]. Applied to imaging element distribution in natural samples at XFM, the result is spatial detail simultaneously spanning 4 orders of magnitude from ~1 µm to ~10 mm.[1] DP Siddons et al., AIP Conference Proceedings 705 (2004) 953. [2] R Kirkham et al., Proc. of SRI'09, AIP Conference Proceedings, in press. [3] CG Ryan, Int. J. of Imaging Systems and Technology 11 (2000) 219. [4] CG Ryan et al., Proc. of ICXOM'09, AIP Conference Proceedings, in press.

Topics

• impedance spectroscopy
• Silicon
• trace element
• fluorescence microscopy