Mass spectrometry of clustered flows during gas ionization by low-temperature plasma in the diffuser part of the nozzle

This paper presents a technique for mass spectrometry of an ionized cluster flow in the variant of its ionization in a supersonic nozzle when gas flows into a rarefied space. The purpose of the implementation of the methodology presented in the work is its further use for conducting research on the initiation of intracluster energy exchange. To ionize the gas flow in the nozzle, a scheme for generating an effective discharge directly in the diffuser part of a supersonic nozzle has been developed and implemented. The results obtained under the conditions of traditional mass spectrometry of neutral fluxes with particle ionization directly in the mass spectrometer detector (EBMS method) and under the conditions of ionization of a supersonic jet at a selected distance from the nozzle by a high-voltage electron beam (HVEB method) are compared with the results obtained by the discharge ionization method in the nozzle (DIN method). It has been experimentally revealed that when using the DIN method, a significantly larger number of ions are formed than when using the HVEB method, which is an undoubted advantage of the developed method. It is shown that the heating of the nozzle leads to some delay in the condensation process, but a relatively small correction of the stagnation pressure compensates for this loss. The results of trial experiments on the search for conditions for ion-cluster energy exchange are presented using the example of an argon-methane mixture flow.