Program

Poster Presentations

Day 2, June 11（Thu.）　　Room P (5F 501+502)

2P-19

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Development of a Bipolar Charger for Nanometer-sized Particles Using an Atmospheric Pressure Plasma Jet

(¹Toyohashi Univ. Tech., ²NIT, Kochi College)
^oKokone Michikura¹, Kenkichi Nagato², Hirofumi Kurita¹

Measurement techniques for the particle size distribution of atmospheric nanometer-sized particles have been gaining attention in various fields. The standard method using a Differential Mobility Analyzer (DMA) requires a pretreatment charging process, typically employing bipolar diffusion charging with radioactive sources such as ²⁴¹Am. Since the use of radioactive sources are strictly regulated in recent years, an atmospheric pressure plasma jet has been studied as a non-radioactive alternative bipolar charger. However, bipolar charging performance of nanometer-sized particles using atmospheric pressure plasma has not been evaluated in detail. In this study, the plasma jet was generated using a capillary-type discharge tube, and the ion characteristics in the afterglow region where particles are actually charged were analyzed. The mass and mobility spectra of positive and negative ions were measured using an API-MS and a drift tube ion mobility spectrometer, respectively. Based on the mean mass and mean mobilities calculated from the measured spectra, we simulated the charging processes for the particle of 1-100 nm. The results demonstrated that the charging probabilities using atmospheric pressure plasma were equivalent to those using ²⁴¹Am.

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