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论文类型：期刊论文

发表时间：2017-11-01

发表刊物：Spectrochimica Acta - Part B Atomic Spectroscopy

收录刊物：Scopus、SCIE、EI、CPCI-S

卷号：137

页面范围：70-76

ISSN号：05848547

关键字：Time-of-flight mass spectroscopy; Laser induced breakdown spectroscopy; Tungsten plasma; Multi-charged ions; Dynamic plasma sheath

摘要：In this work, the plasma was produced by irradiating a tungsten target with an 8 ns pulsed Nd:YAG (λ = 1064 nm) laser in a vacuum chamber under the pressure of 4 × 10 ?4Pa. The optical and particle emissions were systematically investigated using laser induced breakdown spectroscopy and time-of-flight mass spectroscopy respectively. The results showed that not only there were neutral and single ionized atoms in the laser induced plasma, but also quite a number of multi-charged ions were observed. The ion charge state was even up to 6 at the laser power density of ~ 11 GW/cm2. Time and space resolved optical spectroscopy was investigated by using a bundle of lined fibers. Meanwhile, the time-resolved mass spectrometric study of laser produced tungsten plasma was carried out. The variation in intensities of the different species with time showed that higher charged ions reached their peak intensities earlier. This demonstrated that the higher charged ions had higher velocities and the different charged ions were separated during the expansion process. The kinetic energy corresponding to the velocity of the ions was found to increase exponentially with ionic charge state which was related to the acceleration of the dynamic plasma sheath. © 2017 Elsevier B.V.