Diagnosis of active species in reactive acetylene plasma by laser-ionization molecular-beam time-of-flight mass spectrometry

This work reports a new laser molecular beam time-of-flight mass spectrometry (LMB-TOFMS) instrument built at Plasma Spectroscopy Lab in Dalian University of Technology (DUT). The preliminary investigation of the intermediate species distribution of acetylene plasma in an atmospheric-pressure fast-flow nanosecond-pulsed dc-discharge has been carried out. The C H species (x = 4,6,8), believed to be the dominant source of negative ions in C H plasma, have been detected with relatively intense peak signals and some complex radical species like C H , C H , C H are also observed. The addition of Ar gas significantly influenced the detection of the intermediate species. This is might be due to the metastable Ar with energies of 11.5 and 11.7 eV and a long lifetime. The potentialities of LMB-TOFMS for hydrocarbon plasmas diagnosis have been discussed. © 2011 Springer Science+Business Media, LLC.