Further laboratory studies and stratospheric flight of a mass spectrometer beam system

A gas expansion system combined with a mass spectrometer has been tested and flown successfully in the stratosphere. Through a sequence of orifices and high speed pumping, gas particles were formed into a molecular beam and analyzed by a sensitive mass spectrometer. During two balloon flights, vertical profiles of all major atmospheric constituents as well as O(3), CO(2), H(2)O and others were obtained. Gases such as (38)Ar and (16)O(17)O provided in-flight calibration standards. The sensitivity of the system was such that gases with mixing ratios of 10 ppb at an ambient pressure of about 10 mbar were detectable.