Experimental and theoretical studies of particle generation afterlaser ablation of copper with background gas at atmosphericpressure
Laser ablation has proven to be an effective method for generating nanoparticles; particles are produced in the laser induced vapor plume during the cooling stage. To understand the in-situ condensation process, a series of time resolved light scattering images were recorded and analyzed. Significant changes in the condensation rate and the shape of the condensed aerosol plume were observed in two background gases, helium and argon. The primary particle shape and size distribution were measured using a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a differential mobility analyzer (DMA). The gas dynamics simulation included nucleation and coagulation within the vapor plume, heat and mass transfer from the vapor plume to the background gas, and heat transfer to the sample. The experimental data and the calculated evolution of the shape of the vapor plume showed the same trend for the spatial distribution of the condensed particles in both background gases. The simulated particle size distribution also qualitatively agreed with the experimental data. It was determined that the laser energy, the physical properties of the background gas (conductivity, diffusivity and viscosity), and the shape of the ablation system (ablation chamber and the layout of the sample) have strong effects on the condensation process and the subsequent sizes, shapes and degree of aggregation of the particles.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE. Administrator for National Nuclear Security AdminNonproliferation and NationalSecurity Program Direction
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 929332
- Report Number(s):
- LBNL-63255; JAPIAU; R&D Project: 675201; BnR: NN2001000; TRN: US200813%%195
- Journal Information:
- Journal of Applied Physics, Vol. 101, Issue 12; Related Information: Journal Publication Date: 06/2007; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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