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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


The target chamber accommodates two X-ray detectors, one Ge gamma-ray detector and up to four particle detectors (two Canberra PIPS detectors initially). The main X-ray detector is a Ge large area variety and is equipped with an X-ray filter to attenuate intense major element lines. The chamber permits a close geometry with the detector 16 mm from target [1,2]. This is complemented by a second X-ray detector, a 10 mm2 Si(Li) (not shown above), to provide major element detection.

The principal X-ray detector is a Canberra Ultra LE Ge detector, an intrinsic Ge detector with a 100 mm2 active area, a thickness of 10 mm and a measured energy resolution of 143 eV (Mn Ka). The detector uses a Canberra 2060 digital signal processor (DSP) which includes pile-up rejection and is capable of high counts rates, by virtual of the digital filtering approach. The gamma-ray detector is a Canberra 30% Ge detector, with a slim-line preamplifier configuration to insert into the chamber 0 port. The measured energy resolution is 1.9 keV (Co60 1.332 MeV). It uses a second DSP, which includes pile-up rejection, as well as ballistic deficit correction [1].

[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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