Self-calibrating mass spectrometer. Project accomplishment summary for DOE Technology Transfer Initiative project 92-Y12P-055-B1

A mass spectrometer gas analyzer analyzes gas mixtures to determine the type and relative amounts of gases that compose the mixture. Cost of the instrument is usually determined by how sensitive the device is; the more sensitive the measurements, the higher the price. Critical to getting good results from a mass spectrometer gas analyzer is having the instrument calibrated. An uncalibrated instrument will do qualitative analysis, but not quantitative analysis. The purpose of this Cooperative Research and Development Agreement (CRADA) was to develop a way to calibrate a gas analyzer with minimal effort by the operator. Using technology originally developed for nuclear weapons applications, researchers from the Oak Ridge Y-12 Plant and from Vacuum Technology, Inc. (VTI), developed a calibration method that uses metal hydride (hydrogen that is in solid form). The entire sequence is controlled by computer software developed as part of the CRADA research. After calibration, unknown gas samples are introduced, and the resulting mass spectra are compared to reference spectra appropriately adjusted by the instrument response to the calibrating hydrogen pulse. Because the shifts of the mass spectra of a number of common gases can be predicted by the shifts in the hydrogen peak, hydrogen can be used to calibrate the instrument for a variety of gases. Through the pattern recognition ability of the computer software, the analyzer works not only for hydrogen, but for other gases as well