Gas Analyzer

2009-03-09T15:58:00.001-07:00

The Thermal and Evolved Gas Analyzer (TEGA) is a scientific instrument aboard the Phoenix spacecraft. TEGA's design is based on experience gained from the failed Mars Polar Lander. Soil samples taken from the Martian surface by the robot arm are eventually delivered to the TEGA, where they are heated in an oven to about 1,000ºC. This heat causes the volatile compounds to be given off as gases which are sent to a mass spectrometer for analysis. This spectrometer is adjusted to measure particularly the isotope ratios for hydrogen, oxygen, carbon, nitrogen, and heavier gases. Detection values as low as 10 parts per billion. The Phoenix TEGA has 8 ovens, which are enough for 8 samples.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.

Infrared gas analyzer

2009-03-09T15:52:00.000-07:00

An infrared gas analyzer measures trace gases by determining the absorption of an emitted infrared light source through a certain air sample. Trace gases found in the earths atmosphere get excited under specific wavelengths found in the infrared range. The concept behind the technology can be understood when considering the greenhouse effect. When sunlight hits earths surface, the incoming short wave radiation gets turned into long wave radiationlong wave infrared radiation that is reflected back into space. If there is a thick atmosphere on covering the planet of interest, much of this radiation is absorbed by the "greenhouse gases" in our atmosphere which act as a type of insulative blanket. The infrared gas analyzer works using a similar principle.
Normally, the infrared gas analyzer has two chambers, one serves as a reference chamber while the other chamber serves as a measurement chamber. Infrared light is emitted from some type of source on one end of the chamber, passes through series of chambers that contain given quantities of various gases in question. For example, if the analyzer is designed to measure carbon monoxide and dioxide then these chambers must contain a certain amount of these gases. In the design from 1973 (pictured above), the infrared light is emitted from a source where it passes through the sample gas, a reference gas with a known mixture of the gases in question and then through the "detector" chambers containing the pure forms of the gases in question. When a "detector" chamber absorbs some of the infrared radiation, it heats up and expands. This causes a rise in pressure within the sealed vessel that can be detected either with a pressure transducer or with a similar device. The combination of output voltages from the detector chambers from the sample gas can then be compared to the output voltages from the reference chamber.[1]

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Gas Analyzer

Infrared gas analyzer