Plasma confinement by hemispherical cavity in laser-induced breakdown spectroscopy

Section: Introductionmentioning

confidence: 92%

Accuracy improvement of quantitative analysis by spatial confinement in laser-induced breakdown spectroscopy

Guo¹,

Hao²,

Shen³

et al. 2013

“…In the past, researchers only studied the plasma confinement effects using either spatial or magnetic confinement. For instance, our previous research [23] studied the enhancement of plasmas confined with an aluminum hemispherical cavity, resulting in an enhancement factor of 12 for Mn lines of low-concentration Mn element. Rai et al [24] have studied the magnetic field confinement effect in air with a homemade magnetic device, achieving a maximum enhancement factor of 2 for metal alloy samples.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of optical emission from laser-induced plasmas by combined spatial and magnetic confinement

Guo¹,

Wei²,

Zhang³

et al. 2011

Self Cite

115

He, X. N.; Li, C. M.; Zhou, Y. S.; Cai, Z. X.; Zeng, X. Y.; and Lu, Yongfeng, "Enhancement of optical emission from laser-induced plasmas by combined spatial and magnetic confinement" (2011 Abstract: To enhance optical emission in laser-induced breakdown spectroscopy, both a pair of permanent magnets and an aluminum hemispherical cavity (diameter: 11.1 mm) were used simultaneously to magnetically and spatially confine plasmas produced by a KrF excimer laser in air from pure metal and alloyed samples. High enhancement factors of about 22 and 24 in the emission intensity of Co and Cr lines were acquired at a laser fluence of 6.2 J/cm 2 using the combined confinement, while enhancement factors of only about 11 and 12 were obtained just with a cavity. The mechanism of enhanced optical emission by combined confinement, including shock wave in the presence of a magnetic field, is discussed. The Si plasmas, however, were not influenced by the presence of magnets as Si is hard to ablate and ionize and hence has less free electrons and positive ions. Images of the laser-induced Cr and Si plasmas show the difference between pure metallic and semiconductor materials in the presence of both a cavity and magnets.

“…Many methods have been developed to improve the sensitivity of LIBS, such as, dualpulse excitation [8][9][10], spatial or magnetic confinement [11][12][13][14], microwave-assisted LIBS [15], and laser ablation combined with fast pulse discharge [16]. Generation of hightemperature and low-density plasmas in LIBS to improve the spectral resolution has also been achieved by introducing a second laser pulse to re-ablate the laser-induced particles with delays up to milliseconds [17].…”

Section: Introductionmentioning

confidence: 99%

Flame-enhanced laser-induced breakdown spectroscopy

Liu¹,

Li²,

He³

et al. 2014

Self Cite

Liu, L.; Li, S.; He, X. N.; Huang, X.; Zhang, C. F.; Fan, L. S.; Wang, M. X.; Zhou, Y. S.; Chen, K.; Jiang, L.; Silvain, J. F.; and Lu, Yongfeng, "Flame-enhanced laser-induced breakdown spectroscopy" (2014 Abstract: Flame-enhanced laser-induced breakdown spectroscopy (LIBS) was investigated to improve the sensitivity of LIBS. It was realized by generating laser-induced plasmas in the blue outer envelope of a neutral oxy-acetylene flame. Fast imaging and temporally resolved spectroscopy of the plasmas were carried out. Enhanced intensity of up to 4 times and narrowed full width at half maximum (FWHM) down to 60% for emission lines were observed. Electron temperatures and densities were calculated to investigate the flame effects on plasma evolution. These calculated electron temperatures and densities showed that high-temperature and low-density plasmas were achieved before 4 µs in the flame environment, which has the potential to improve LIBS sensitivity and spectral resolution.