Calibration of Polarization-Sensitive and Dual-Angle Laser Light Scattering Methods Using Standard Latex Particles

Chang, Hyunju; Fujishige, Yousuke; Okuyama, Kikuo

doi:10.1006/jcis.2001.7707

Cited by 14 publications

(3 citation statements)

References 22 publications

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“…The pressurized nebulizer (Nanomaster, JSR Corp., Tokyo, Japan) was used to atomize suspensions into aerosol particles. This nebulizer was equipped with an ejector to break liquid threads into droplets and resulting aerosol particles, and was proven effective in generating aerosol particles with good monodispersion (a standard geometric deviation of <1.2) and high concentration (19). The nebulizer was fed with pressurized, clean air and, at a typical airflow rate of 35 L/min, was operated at an inlet pressure of 0.25 MPa, an ejector pressure of 0.20 MPa, and with pressure applied to the suspension at 0.25 MPa.…”

Section: Methodsmentioning

confidence: 99%

Development and Evaluation of an Aerosol Generation and Supplying System for Inhalation Experiments of Manufactured Nanoparticles

Shimada

Wang

Okuyama

et al. 2009

Environ. Sci. Technol.

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Risk assessment of nanoparticles by inhalation experiments is of great importance since inhalation is considered the most significant route of exposure to nanoparticles suspended in air. However, there have been few inhalation experiments using manufactured nanoparticles, mainly because of the difficulty in stably dispersing the nanoparticles in air for a long period of time. In this study, we report for the first time the development of a rational system for stably and continuously dispersing and supplying manufactured nanoparticles for inhalation experiments. The system was developed using a spray-drying technique, in which a nebulizer was used to atomize nickel oxide (NiO) and fullerene (C60) nanoparticle suspensions, and the resulting droplets were dried to generate aerosol nanoparticles. The size, concentration and morphology of the aerosol particles were evaluated by in-line measurements using an aerosol measuring device and off-line measurements based on the collection of the aerosol particles. After examining the effects of the conditions for the suspensions and the aerosol generation, we were able to obtain NiO and C60 aerosol nanoparticles with average diameters of 53-64 and 88-98 nm, respectively. By feeding these aerosols into a whole-body exposure chamber for rats, a stable supply of the aerosol nanoparticles could be achieved for long hourly durations (6 h per day) as well as for long terms (5 days per week for 4 weeks).

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Section: Methodsmentioning

confidence: 99%

Development and Evaluation of an Aerosol Generation and Supplying System for Inhalation Experiments of Manufactured Nanoparticles

Shimada

Wang

Okuyama

et al. 2009

Environ. Sci. Technol.

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“…This setup enabled detection of scattered laser light by particles with the CCD camera (i.e. the LLS technique), and was used to monitor spatial particle distributions [2,7,34,[47][48][49]. While LLS can have single-particle sensitivity, emission from plasmas leads to large interferences in the visible wavelength range, hence the laser wavelength needs to be chosen properly to not coincide with an Ar emission wavelength, the optical signal received by the camera must be filtered, and background subtraction is often necessary [50].…”

Section: Laser Light Scatteringmentioning

confidence: 99%

Material-dependent submicrometer particle trapping in capacitively-coupled plasma sheaths in an intermediate collision regime

Ono¹,

Kortshagen²,

Hogan³

2021

Plasma Sources Sci. Technol.

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Understanding submicrometer particle behavior in non-thermal capacitively coupled plasmas (CCPs) is important in the application of CCP reactors in thin-film vapor deposition; nucleated and resuspended particles can deposit on thin films, forming defects. Prior studies of supermicrometer particle behavior in CCP reactors have revealed that particles are trapped in the pre-sheath or sheath regions near electrodes, but have examined in detail neither the trapping of submicrometer particles, nor the influence of particle material properties on trapping. Using laser light scattering (LLS), we examined trapping of submicrometer metal oxide particles (radii in the 211 nm–565?nm range) of 6 distinct material compositions in the pre-sheath/sheath region of a CCP reactor operated at pressures in the 0.5–2.0 Torr range. We specifically focus on trapping near the upper electrode of a horizontally-oriented reactor. In this instance, trapping is brought about by a balance between electrostatic forces and gravitational forces driving particles away from the electrode, with ion drag forces driving particles toward the electrode. LLS measurements reveal that submicrometer particles are trapped near the upper electrode for all particle sizes, types, and operating pressures, with the trapping location at an increased distance away from the electrode with decreased CCP reactor pressure. Interestingly, we find the trapping location shifts slightly farther from the top electrode with increasing material dielectric constant. This suggests that the ion drag force is influenced by particle material properties, though in an unclarified manner. Measured trapping locations are also compared to model predictions where particle charge levels and the ion drag force are calculated using expressions based on ion trajectory calculations in a plasma sheath accounting for ion–neutral collisions. Predicted ion densities required for trapping are a factor of 6–16 higher than calculated at the observed particle trapping locations when applying a dissipative ion–particle encounter model, with more substantial disagreement found when considering a non-dissipative encounter model. In total, our results confirm that submicrometer particle trapping occurs at the upper electrode of CCP reactors, which must be facilitated by a balance largely between electrostatic and gravitational forces opposed by ion drag forces, but suggest future studies will be required to understand how particle material properties affect forces on particles on the plasma volume boundary, and how the ion drag force is sufficiently high to facilitate trapping.

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“…Shiratani et al measured two-dimensional distributions of size and density of particles generated in a plasma reactor using polarization sensitive light scattering method (9). Shimada et al carried out calibration experiments of system based on polarization sensitive light scattering and dual angle light scattering methods using polystyrene latex particles (10). But all these scattering methods for one or two-dimensional measurement are based on the Mie scattering theory for spherical particles.…”

Section: Introductionmentioning

confidence: 99%

Planar laser light scattering technique for measurement of nonspherical particles

et al. 2004

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Small particles are one of the biggest sources that cause loss in semiconductor and flat panel display industry. Therefore, it is important to control them during their manufacturing process. To achieve this goal, exact measurement of particles is first required. Laser light scattering is the most widely used technique for diagnosis of particles because it does not disturb flow field and enables real time and spatially resolved analysis. Measurement of nonspherical aggregates comprised of small primary particles is difficult compared with spherical particles because they have very complex morphology. In addition, most researches on aggregates using light scattering are limited to point measurement. Motivated by this, we have developed a laser light scattering method for simultaneous measurement of spatial distributions of aggregate size and morphology. Silica aggregates that were generated in methane/air premixed flame were used as test particles. Multiangular planar light scattering measurement was carried out and the result was interpreted based on the Rayleigh-Debye-Gans scattering theory for fractal aggregates to obtain the mean radius of gyration and fractal dimension that are the parameters characterizing aggregate size and morphology. The suitability of our new technique was confirmed by experiment using conventional light scattering.

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Calibration of Polarization-Sensitive and Dual-Angle Laser Light Scattering Methods Using Standard Latex Particles

Cited by 14 publications

References 22 publications

Development and Evaluation of an Aerosol Generation and Supplying System for Inhalation Experiments of Manufactured Nanoparticles

Development and Evaluation of an Aerosol Generation and Supplying System for Inhalation Experiments of Manufactured Nanoparticles

Material-dependent submicrometer particle trapping in capacitively-coupled plasma sheaths in an intermediate collision regime

Planar laser light scattering technique for measurement of nonspherical particles

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