New way to build a high-performance gas-dynamic interface to produce and transport ions into a mass analyzer

A new way to form the supersonic gas flow for producing and transportation the ions under study without their significant loss into a mass analyzer is described. The main objective of the paper is to show a relevancy of the approach. For both the argon–xenon gas mixture and atmospheric air fed as supersonic flow and in an effusion mode, the distributions of density for the recorded ions across their moving direction as well as other experimental dependencies were measured. The results of these measurements may be explained by formation of a supersonic gas flow with a divergence which is significantly smaller than the predicted one by “evident” model. The data analysis shows that only very small fraction of the ions formed inside the supersonic gas flow is recorded by the existing system. To eliminate these difficulties, it is suggested to turn the ions from the gas flow in the direction orthogonal to the initial one using two-grid electrostatic mirror before inserting the ions into the time-of-flight mass spectrometer with orthogonal injection of ions. The computer simulation has shown efficiency of such an approach.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (194 K)Download as PowerPoint slideHighlights► Supersonic gas flow formation inside a capillary is confirmed experimentally. ► The estimated divergence of Ar flow corresponds to the temperature below 0.01 K. ► Divergence of the air flow through capillary corresponds to similar temperature. ► Gas molecules mirror reflection from capillary walls may explain flow properties. ► Two-grid mirror reflection is proposed to record effectively ions from the flow.