Data Acquisition and Analysis
For every event recorded by a detector, an E,X,Y triplet is saved, tagged by the detector number,
as a record of the energy (E) and coordinate (X,Y) of the event in the image area. This event data
stream is analyzed using the new GeoPIXE II
software package for quantitative analysis of PIXE
data in order to
image element distribution using Dynamic Analysis.
Dynamic Analysis is a powerful algorithm, developed at the CSIRO for unmixing elemental signatures
in proton induced X-ray spectra in real-time, in order to project quantitative images of trace
and major element spatial distribution in the sample under study.
Data Acquisition uses the MicroDAS interface, developed by the MARC group
at Melbourne University, based on a general purpose digital I/O card and a Pentium
PC running Linux. This approach uses the DSP units for both X-ray and gamma-ray detector
channels and conventional Wilkinson ADCs for the particle detectors. Four detector
channels are supported presently.
The PC directly generates the scan drive, with a typical dwell per pixel of 100 µs,
via two 16 bit DACs,
and is capable of count-rates in excess of 100,000 counts per second. The Linux PC is
networked to the Amiga workstation which controls the target goniometer and beam-shaping systems [1,2].
 C.G. Ryan, D.N. Jamieson, W.L. Griffin, G. Cripps and R. Szymanski, "The New
CSIRO-GEMOC Nuclear Microprobe: First Results, Performance and Recent Applications",
Nucl. Instr. Meth. B181 (2001) 12-19.
 C.G. Ryan, D.N. Jamieson, W.L. Griffin and G. Cripps, "The CSIRO-GEMOC Nuclear Microprobe:
A high-performance system based on a new closely integrated design", Nucl. Instr. Meth. B158 (1999) 97-106.