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Gravimetric Preparation of Primary Standard Gas Mixtures in the Parts Per Trillion Range.
Loya-EW; Seitz-CA; Emerson-DE
MISSING :4 pages
A method for preparing gravimetric primary standards of helium in the parts per trillion range has been developed by the Bureau of Mines. The standards are used to calibrate a specially modified mass spectrometer used in determining the abundance of helium-3 and helium-4 in geochemical samples and of helium-3 in isotopically purified helium-4. The desired gas standards are prepared in 5-kg metal cylinders filled to 1,800 psia. Relative errors of less than 1 pct have been attained in the parts per trillion range using a successive dilution technique.
IH; Report of Investigations
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division