کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1239822 1495723 2012 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Tomography of single and double pulse laser-induced plasma using Radon transform technique
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Tomography of single and double pulse laser-induced plasma using Radon transform technique
چکیده انگلیسی

The Radon transform tomography is used for reconstruction of the emissivity distribution in single- (SP) and double-pulse (DP) laser induced plasmas in orthogonal geometry. The orthogonal DP plasma is intrinsically asymmetric and thus suitable for the Radon reconstruction. The DP plasma consists of two plasmas separated by a short time interval of ~ 1 μs. The first plasma is created in air near the surface of a Si wafer and is followed (pre-ablation mode) or preceded (post-ablation mode) by the second plasma induced on this surface. A spectrometer moves in a semi-circular path around the plasma keeping the plasma in the rotation center. The optical detection is arranged so that a thin plasma layer parallel to the target surface is monitored. The axial symmetry of the SP plasma is investigated by comparing data from the Abel inversion taken at different angles and Radon reconstruction. The multi-angle measurements are used to estimate errors of the Abel reconstruction due to asymmetries of the plasma. Time-resolved Radon reconstruction in white light is performed for the DP plasma in both pre- and post-ablation modes. In the former case, the effect of ablated aerosol on the formation of the air plasma is monitored. In the latter case, a formation of an asymmetric compression shock created by the target plasma inside the air plasma is visualized. This observation is supported by computer simulations. An interaction of the two plasmas is studied by spectrally resolved Radon reconstruction revealing a complex distribution of target and ambient species inside the plasma at all studied delay times. Overall, it is demonstrated that Radon-based tomography is an informative tool to study transient asymmetric laser induced plasmas.


► Optical tomograph is constructed to monitor asymmetric laser induced plasmas.
► Spectrally resolved Radon reconstruction of asymmetric plasmas is carried out.
► Propagation of a shock wave is visualized and confirmed by computer simulations.
► Errors of Abel reconstruction due to plasma asymmetry are analyzed.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Spectrochimica Acta Part B: Atomic Spectroscopy - Volume 76, October 2012, Pages 203–213
نویسندگان
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