Science in Practice Portal

The Bureau of Land Management's Helium Operations office in Amarillo, Texas, has developed a mass spectrometer method to determine percent-range helium in gaseous mixtures. Activated coconut charcoal at liquid nitrogen temperature is used to adsorb components other than helium in the mixture. A modified helium leak detector mass spectrometer is then used to detect the resulting helium "pressure peak." The digitized peak of the unknown sample is compared directly to that of a high-purity helium calibration standard. This method has been demonstrated to be accurate to within +0.1 pet over the concentration range of about 30 to 100 pet helium.