XT Series Residual Gas Analyzer

The most stable single quadrupole RGA you can buy

The RF generator is engineered to the limits of what the physics allows, and stability is what that buys you. Extorr systems typically run for years without drifting out of calibration or needing to be retuned. For anyone building an instrument or a process around an RGA, that is usually the deciding factor: the measurement you take tomorrow is comparable to the one you took today.

Three instruments in one probe

A Pirani gauge sits in the base of the feedthrough and a Bayard-Alpert type ion gauge is built into the ionizer, each with its own amplifier. You get total pressure from atmosphere to UHV and partial pressures from the quadrupole, on one 2.75" CF port. The gauges also act as a fail-safe interlock: the filament and electron multiplier are shut down before a pressure excursion can damage them, and you can leak check at any pressure, not just below 10^-4 Torr.

A measured total pressure, not a derived one

Many RGAs report total pressure by adding up the partial pressures they measure. That sum inherits every error in the spectrum, and it decays along with the ionizer as it ages.

The XT measures total pressure with a genuine Bayard-Alpert type ion gauge built alongside the ionizer, with its own collector and amplifier. It runs at much higher ion energies than the 5–10 eV the quadrupole needs, which makes it far less sensitive to ionizer aging. It is an independent measurement rather than a derived number — and it gives you an on-board reference to calibrate the partial pressures against as the ionizer ages.

Nine orders of magnitude in a single scan

A single wide dynamic range amplifier reads ion currents from 10^-6 down to 10^-15 A, ranging automatically and seamlessly as the scan runs. Partial pressures from 10^-4 to 10^-11 Torr, or below 10^-14 Torr with the electron multiplier, captured in one spectral scan without any setup on your part.

Filaments that survive mistakes, and that you replace yourself

The filament assembly is thoria coated iridium, and it is protected against vacuum excursions by both the Pirani and the ion gauge. The most common way to kill an RGA filament — running it into a pressure it shouldn't see — simply doesn't happen here, because the gauges shut it down first.

Snap-in electron multiplier

The multiplier snaps in and out by hand with a clean glove: no tools, no probe disassembly. The CCU meters out only as much current as it needs, avoiding the destructive channel current that kills multipliers during an overpressure event. Covered by a one year warranty against failure.

Compact, fan-less, self-supporting

An efficient RF generator design means no cooling fan — no vibration, no dust drawn into high voltage electronics, and one less thing to fail in a clean room. The probe is rigid enough to stand on its own, so it needs no support nipple and can reach well into the chamber. The CCU extends 6.2" from the flange face and detaches with two thumb screws for bakeout.

Diagnosable without shipping it back

The software exposes a full diagnostics page for the probe and electronics. Send us that log and we can usually tell you exactly what is wrong — over 90% of faults are resolved by phone or email. Support comes from the people who designed the instrument.

Software included, upgrades free

Every system ships with VacuumPlus, which gives complete access to probe and electronics settings rather than a fixed set of modes. Spectra, trends, leak detection and total pressure in real time, data in Torr, Pascal or amps, and export for analysis. All versions are free downloads, forward and backward compatible.

Gas that is not already in vacuum

If what you want to measure is not already under vacuum, the analyzer can be mounted in a pumped manifold of its own, with the gas admitted through a restriction.

We supply the parts for this: manifolds, sampling inlets, capillary, and the turbo pumping station. Design a Custom Mass Spectrometer walks through the design process and is worth reading before you order.