Helix SFT Static Vacuum Mass Spectrometer

The HELIX SFT (Split Flight Tube) mass spectrometer is a magnetic sector mass spectrometer designed for high-precision isotope analysis of small samples of noble gases. It consists of a magnetic sector analyzer with a 35 cm 120° extended geometry ion optic. This geometry combines excellent ion optical performance with bi-directional focusing and high dispersion.

Performance Details

1. Ability to measure both helium isotopes simultaneously. No apex jump required. Result in reduced analysis time and greater productivity.
2. Abundance sensitivity: The mass contribution of 4 to mass 3 is < 1 ppb. In comparison the 5400 / MAP215 has a mass specification of 1 ppm of 40 at 39.
3. Volume: The internal volume of the HELIX SFT system is ~1400 cc.
4. Resolution: The low mass detector, where helium 3 is measured, has a resolution > 700, which ensures that helium 3 is completely separated from the two interferences HD and H.
5. 1010/1011/1012 amplifiers with 50 volt range allow most analyzes to be performed on durable Faraday detectors.

Ion Source
The HELIX SFT system uses a flange-mounted “Nier” type ion source that has evolved in design over the last 30 years. This source provides excellent sensitivity while maintaining a low trapping/total emission ratio leading to long filament life and low source temperatures. It is designed for easy removal and changing of the filament. Source self-aligns on assembly.

• Self-aligning source filament
• Maximized ion production for high sensitivity
• Simple design, easy to maintain

Electrostatic Analyzer
The HELIX SFT low mass collector includes a 5 cm energy 90-degree filter, which allows the system to measure immense ratios regardless of peak tailings. The specification for sensitivity is <1 ppb for adjacent masses (3 contributions out of 4) at 1 x 10-7 mbar. Note the individual partial pressures of the other  gasses present, including Neon and Argon, must be less than 5% that of Helium.