Figures & data
FIG. 1 Schematic illustration of the charging of aerosol nanoparticles by the ion beam. The nanoparticles were charged by the direct impact of the beam and secondary electrons generated from the surrounding He gas.
FIG. 2 The pressure dependence of the ion current and electron density measured by the ion probe at the aerosol stream.
FIG. 3 Change in the combination coefficient for initially (a) neutral particles and (b) charged particles.
TABLE 1 Mobility of ions and electrons in He used in the calculation (100 Pa)
FIG. 4 Experimental system used in this study. (case 1) Evaluation of charging probability of monodispersed particles, (case 2) tandem LP-DMA system, and (case 3) charging of polydisperse neutral particles.
FIG. 5 Change in the current of monodispersed particles with a mobility diameter of 19 nm against acceleration energy. The AEC was operated under both positive and negative modes.
FIG. 6 Size distribution of Si nanoparticles measured by LP-DMA and AEC. Change in the current by ion beam irradiation after the classification. Initially (a) positive and (b) negative particles were charged by the IBAC, respectively.
FIG. 7 The ratio of the current with/without charging by the IBAC for (a) negative and (b) positive mode operation of the AEC. LP-DMA-classified particles with an initially positive charge were used as test aerosol.
FIG. 8 Change in the mobility spectrum of monodispersed particles measured by the second LP-DMA. The particles are classified by the first LP-DMA to be (a) 5 × 10−6, (b) 3 × 10−6 in mobilities for He+ ion beam and (c) 5 × 10−6, (d) 3 × 10−6 in mobility for Ar+ ion beam.
FIG. 9 Size dependency of the calculated charging probability against particle diameter. The properties of (a) He+ and O2 ions and (b) He+ and electron were used in the calculation.
FIG. 10 Change in the size distribution of Si nanoparticles with trapping by the first AEC and with ion beam charging of the initially neutral particles.
