Some improvements on the particle beam generator

Kievit, O.; Marijnissen, J.C.M.; Verheijen, P.J.T.; Scarlett, B.

doi:10.1016/0021-8502(90)90335-u

Cited by 14 publications

(12 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…len and Gould 1981;Hall and Beeman 1976;Seapan et al 1982;Sinha and Friedlander 1986). Narrow particle beams with small divergence angles are desirable in many applications in order to achieve high transport efficiencies of particles from a sampling regime to a detector and high resolution of particle size measurements (Dahneke and Flachsbart 1972;Estes et al 1983;Kievit et al 1990;Sinha et al 1982). Such beams can be obtained by using sheath air to confine the aerosol flow to a narrow region near the axis upstream of the nozzle.…”

Section: Introductionmentioning

confidence: 99%

Generating Particle Beams of Controlled Dimensions and Divergence: I. Theory of Particle Motion in Aerodynamic Lenses and Nozzle Expansions

Liu

Ziemann

Kittelson

et al. 1995

Aerosol Science and Technology

503

420

View full text Add to dashboard Cite

A particle beam is produced when a particle-laden gas expands through a nozzle into a vacuum. This work discusses the theoretical basis of a novel method for producing highly collimated and tightly focused particle beams. The approach is to pass the particle-laden gas through a series of axisymmetric contractions and enlargements (so-called aerodynamic lenses) before the nozzle expansion. Particles are moved closer to the axis by a lens if the particle sizes are less than a critical value and particles can be confined very closely to the axis by using multiple lenses in series. Since particles close to the axis experience small radial drag forces, they stay close to the axis during nozzle expansion and therefore form a narrow particle beam downstream. The major effects that limit the minimum beam width are Brownian motion and lift forces on particles during the nozzle expansion. Simple theoretical models are developed in this work to estimate the minimum particle beam width set by these effects. While the Brownian-motion effects occur for all types of particles, the lift-force effects only occur for nonspherical particles but are often much greater than the Brownian-motion effects.

show abstract

Section: Introductionmentioning

confidence: 99%

Generating Particle Beams of Controlled Dimensions and Divergence: I. Theory of Particle Motion in Aerodynamic Lenses and Nozzle Expansions

Liu

Ziemann

Kittelson

et al. 1995

Aerosol Science and Technology

503

420

View full text Add to dashboard Cite

show abstract

“…The development of an aerodynami c focusing lens to concentrate aerosols to a beam with high ef® ciency covering a broad pressure and particle size range has been a re markable accomplishment. Early attempts of particle focusing were made with simple capillaries to transfer aerosols into s vacuum chambers Dahneke and Flachsbart 1972;Shina et al 1982;Kievit et al . 1990 .…”

Section: Introductionmentioning

confidence: 99%

Focusing of Aerosols into a Particle Beam at Pressures from 10 to 150 Torr

Schreiner¹,

Schild²,

Voigt³

et al. 1999

Aerosol Science and Technology

View full text Add to dashboard Cite

The study of aerosols including chemical an alysis h as been substantially advanced after the development of aerodynamic focusing lenses. Test results of 2 such lenses are presented; 1 operating at pressures between 15 and 80 Torr an d the other at higher pressures between 30 and 175 Torr. The lenses consist of 7 single ori® ces separated by spacers and contained in a tube of abou t 10 cm in () length. Ori® ce diameters ran ge from 1.40 to .25 mm, while the exit holes nozzles are smaller. Lamin ar gas¯ow within a lens produces a n arrow particle beam wh ich is directed into a vacuum chamber for an alysis of beam width an d position, aerosol transport ef® ciency, linearity, and other parameters. The lenses were tested () both with spherical monodisperse oil particles .34± 4 m m diameter as well as () nonspherical solid NaCl particles .19± .85 m m simulating larger particles with lower density. Both lenses produce narrow aerosol beams with diameters smaller than 4 mm abou t 90 mm downstream of the nozzle. Although nonspherical particles broaden the aerosol beam by a factor of 2± 4, this fact allows a distinction between liquid and solid nonspherical aerosols. Beam ch aracteristics are well reproduced wh en lenses are dis-an d reassembled. The transmission of aerosols through each of the 2 lenses is a nearly linear function of the pressure. Transmission ef® ciencies have been measured to be above 90%.

show abstract

“…Single‐particle on‐line aerosol mass spectrometric techniques became available in different research groups at the beginning of the last decade 11–20. However, the origins of on‐line single‐particle mass spectrometry are considerably older 21.…”

mentioning

confidence: 99%