The Stanford Research Systems RGA200 is a residual gas analyzer for vacuum system diagnostics, measuring partial pressures across a 1–200 amu mass range. The instrument combines a quadrupole probe, electronics control unit (ECU), and Windows-based software for real-time gas composition analysis and system monitoring.
Technical Specifications
Mass Range & Resolution
• 1 to 200 amu
• Better than 1 amu resolution at 10% peak height; adjustable to constant peak width across the mass range
Dynamic Range & Detection
A single scan covers 6 orders of magnitude with a temperature-compensated logarithmic electrometer detecting ion currents from 10⁻⁷ to 10⁻¹⁵ amps at better than 2% precision. Detection limits depend on detector choice:
• Faraday Cup: 5 × 10⁻¹¹ Torr
• Electron Multiplier: 5 × 10⁻¹⁴ Torr
(Measured at 28 amu, 1 amu peak width, 10% height, 70 eV electron energy, 12 eV ion energy, 1 mA emission current)
Sensitivity
• Faraday Cup: 2 × 10⁻⁴ A/Torr
• Electron Multiplier: <200 A/Torr
User-adjustable throughout the high voltage range.
Operating Conditions
• Pressure: 10⁻⁹ Torr maximum; specifications support operation to 10⁻¹⁴ Torr
• Temperature: 70 °C maximum
– Key Features
Ion Source & Filament
Open cylindrical-symmetry ion source uses electron impact ionization with a dual thoriated-iridium (ThO₂/Ir) filament for extended service life. Built-in electron impact desorption enables ion source degassing to minimize background noise. Firmware-driven protection detects overpressure (675 Hz) and automatically shuts off the filament.
Detector Options
Standard Faraday cup detector measures partial pressures from 10⁻⁵ to 5 × 10⁻¹¹ Torr. Optional continuous dynode electron multiplier (CDEM) extends sensitivity to 5 × 10⁻¹⁴ Torr with faster scan rates and improved stability; user-replaceable.
– Compatibility & Integration
The probe mounts on a standard 2.75" Conflat flange and requires 2.5" clearance in the vacuum chamber. Rugged stainless steel construction with self-aligning components reduces outgassing. The ECU (9.1" × 4.1" × 3.1", 6 lbs) separates from the probe for independent high-temperature bake-outs. Field-replaceable filament cartridge and detector modules simplify maintenance.
