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VG 9000

▶ Glow Discharge Source
The ion source has been designed for sensitivity and ease of use. A series of plug-in discharge cells enables the analysis of both pin and flat sample geometries.

Conductors, semiconductors and superconductors are analyzed directly in the plasma. Inorganic insulating solid samples are analyzed using the patented secondary cathode system; insulating powder samples may be compacted with a high-purity conducting binder prior to analysis. Depth profile analysis is performed using the flat sample geometry.

▶ Source Cryo Cooling All cells are cooled to near liquid nitrogen temperatures using Thermo Elemental's patented cryo cooling system to minimize molecular interference species. Cryo-cooling also allows the routine analysis of low melting point samples such as gallium.
In the example above, potassium has been determined with and without cooling. When the system is run "warm," the ArH molecular species is present at approximately 800 ppm, and the resultant peak swamps the trace level potassium signal even at high resolution. Cooling dramatically reduces the ArH polyatomic to 0.5 ppm, enabling the potassium level to be clearly identified.

▶ Double-Focusing Mass Analyzer
A reverse geometry Nier Johnson double-focusing mass analyzer first deflects the ion beam by mass-to-charge ratio around the magnetic sector, focusing at the first focal point between the magnet and the Electro-Static Analyzer (ESA). The ESA then deflects and focuses the ion beam by ion energy to the final focal point at the final slit in front of the detector system. This combination gives the VG9000 a resolving power of around 8000, easily separating overlapping or interfering isotopes.

▶ Faraday and Daly Detector System

Dual Faraday and Daly detectors give the VG9000 11 orders linear dynamic range. The Faraday detector measures the majors within the sample that produce ion currents between 10-13 amps and 10-9 amps. The Daly detector system measures the minor and trace concentrations. System software automatically calibrates and switches between the two detectors, providing seamless data acquisition and analysis.

▶ Choice of Pumping Systems
The VG9000 offers a choice of two pumping systems:

- An all turbo version incorporating a 500 l/s turbo-molecular pump on the source chamber and two 250 l/s turbo-molecular pumps on the analyzer chamber.

- Alternatively, the system may be fitted with a 1500 l/s cryo-pump on the source, which provides more efficient pumping of atmospherics and better limits of detection on carbon, nitrogen and oxygen.