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The CSIRO-GEMOC Nuclear Microprobe

System Overview

Lens System

Beam Shaping Controls

Scanning, Beam Deflection


Data Acquisition and Analysis

Target Chamber

Return to NMP microanalysis

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].

[1] 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.

[2] 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.

For further information contact: Dr. Chris Ryan via email: (
Phone +61-3-9905 9087
Fax orders +61-7-3327 4455
CSIRO Exploration and Mining
Bayview Road, Clayton VIC 3168
CSIRO Australia

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