Australian Scientific Instruments Pty. Ltd. - SHRIMP RG

The Sensitive High Resolution Ion Micro Probe RG is a high precision Secondary Ion Mass Spectrometer (SIMS) with reverse geometry. Ion microprobes make in situ isotopic and chemical 'surface' analysis of solid targets by bombarding the sample with an ion beam with a diameter of several microns typically employing Kohler focussing. The high mass resolution of SHRIMP is achieved by the use of double-focussing mass spectrometer (simultaneous energy and mass refocussing) with a very large turning radius of Magnet and Electrostatic Analyser. SHRIMP has many applications: zircon dating in copper-uranium-gold-silver deposits, uranium-lead dating of sulphur in the sulphide minerals that form metal ores, the isotopic composition of sulphur in the giant base metal ore bodies.

SHRIMP RG is a derivative of SHRIMP II. SHRIMP RG was designed by Prof. William Compston (ANU) and Dr. Steve Clements, based on geometrical principles developed by Prof. Matsuda and manufactured and developed by scientists and engineers at the Australian National University (ANU).

The major modifications to the configuration of SHRIMP II that exist in SHRIMP RG are:

• The position of the mass and energy filter elements are reversed
• The addition of the QQH chamber between the secondary ion beam extraction elements and the magnet.

These features have produced an increase in the mass resolution of the instrument of up to a factor of 20. The operating principle of SHRIMP RG remains similar to that of SHRIMP II.