An optical method is developed for the precise mass determination of submicron size charged particles. The measurement is carried out in a hyperbolic quadrupole ion trap electrode system in vacuum by adjusting particle trajectory star shape patterns. This method does not involve gravity so this may be suitable to use in space applications in weightlessness. Due to the imperfect electrode alignment of the ion trap the mass/charge ratio can now be calculated by means of the corresponding electrical parameters with a relative accuracy of 103. Since the measured parameter is frequency the relative accuracy of the mass measurement could later be increased to 106. Combined with stepwise electron loss events induced by UV radiation it is possible to determine the mass of a single particle in the 109–1012 amu range with similar precision. These findings would seem to indicate the feasibility of a novel optical method for high precision mass determination of a single particle in the submicron diameter range.
In situ, real-time, mass selective energy analysis of the incoming ions has been carried out during bias enhanced nucleation for diamond chemical vapor deposition. The dependence of ion energies and fluxes as a function of the bias voltage and CH4 concentration was measured. The main ionic species that strike the substrate surface during bias enhanced nucleation have energies between 50 and 80 eV and are characterized by a low H content. When the bias is lowered to the value at which nucleation enhancement becomes negligible (100 V in our system), ions have an energy of about 30–40 eV, which is the critical value for penetrating below the surface of a hydrogenated amorphous carbon layer. These findings strongly support the subplantation model of bias enhanced nucleation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.