Residual gas analyzer

A residual gas analyzer (RGA) is a small and usually rugged mass spectrometer, typically designed for process control and contamination monitoring in the semiconductor industry. Utilizing quadrupole technology, there exists two implementations, utilizing either an open ion source (OIS) or a closed ion source (CIS). RGAs may be found in high vacuum applications such as research chambers, surface science setups, accelerators, scanning microscopes, etc. RGAs are used in most cases to monitor the quality of the vacuum and easily detect minute traces of impurities in the low-pressure gas environment. These impurities can be measured down to 10 − 14 Torr levels, possessing sub-ppm detectability in the absence of background interferences.

RGAs would also be used as sensitive in-situ, helium leak detectors. With vacuum systems pumped down to lower than 10 - 5Torr—checking of the integrity of the vacuum seals and the quality of the vacuum—air leaks, virtual leaks and other contaminants at low levels may be detected before a process is initiated.

Residual Gas Analyzer

Residual Gas Analyzer RGA100, RGA200 and RGA300

100, 200 and 300 amu systems Better than 1 amu resolution 6 orders of magnitude dynamic range in a single scan 5 x 10-14 Torr detection limit RGA Windows and LabVIEW software Field-replaceable electron multiplier and filament RS-232 interface Residual Gas Analyzer Analyzer Rear Panels The 100, 200 and 300 amu residual gas analyzers from SRS offer exceptional performance and value. These RGA's provide detailed gas analysis of vacuum systems at about half the price of competitive models. Each RGA system comes complete with a quadrupole probe, electronics control unit (ECU), and a real-time Windows software package that is used for data acquisition and analysis, as well as probe control. Rugged Probe Design The probe consists of an ionizer, quadrupole mass filter and a detector. The simple design has a small number of parts which minimizes outgassing and reduces the chances of introducing impurities into your vacuum system. The probe assembly is rugged and mounts onto a standard 2 ¾ inch CF flange. It is covered with a stainless steel tube with the exception of the ionizer which requires just 2 ½ inches of clearance in your vacuum system—about that of a standard ion gauge. The probe is designed using self-aligning parts so it can easily be reassembled after cleaning. Dual ThO2/Ir Filament Electron Multiplier Compact Electronics Control Unit The densely packed ECU contains all the necessary electronics for controlling the RGA head. It is powered by either an external +24 VDC (2.5 A) power supply or an optional, built-in power module which plugs into an AC outlet. LED indicators provide instant feedback on the status of the electron multiplier, filament, electronics system and the probe. The ECU can easily be removed from the probe for high temperature bakeouts. Unique Filament Design A long-life, dual thoriated-iridium (ThO2/Ir) filament is used for electron emission. Dual ThO2/Ir filaments last much longer than single filaments, maximizing the time between filament replacement. Unlike other designs, SRS filaments can be replaced by the user in a matter of minutes. Continuous Dynode Electron Multiplier A Faraday cup detector is standard with SRS RGA systems which allows partial pressure measurements from 10-5 to 5 × 10-11 Torr. For increased sensitivity and faster scan rates, an optional electron multiplier is offered that detects partial pressures down to 5 × 10-14 Torr. This state-of-the-art macro multi-channel continuous-dynode electron multiplier (CDEM) offers increased longevity and stability and can also be replaced by the user—a first for RGAs! RGA Heater Jacket Useful Features All RGAs have a built-in degassing feature. Using electron impact desorption, the ion source is thoroughly cleaned, greatly reducing the ionizer's contribution to background noise. A firmware driven filament protection feature constantly monitors (675 Hz) for over pressure. If over pressure is detected, the filament is immediately shut off, preserving its life. A unique temperature-compensated, logarithmic electrometer detects ion current from 10-7 to 10-15 Amps in a single scan with better than 2 % precision. This huge dynamic range means you can make measurements of small and large gas concentrations simultaneously. Complete Programmability Communication with computers is made via the RS-232 interface. Analog and histogram (bar) scans, leak detection and probe parameters are all controlled and monitored through a high-level command set. This allows easy integration into existing programs.