TY - JOUR
T1 - Effect of Plasma Gas and the Pressure on Spatially and Temporally Resolved Images of Copper Emission Lines in Laser Induced Plasma Optical Emission Spectrometry
AU - Weng, Julian
AU - Kashiwakura, Shunsuke
AU - Wagatsuma, Kazuaki
N1 - Funding Information:
This work was conducted under a scholarship provided to one of the authors (J. W.) by the Japan Student Services Organization (JASSO). This research was supported by a Grant-in-Aid from the Ministry of Education, Science, Sports and Culture of Japan. (No. 17H01903). The authors are grateful to Nippon Steel Corp., Japan, for a Grant for LIBS research (2019).
Publisher Copyright:
© 2021. The Japan Society for Analytical Chemistry. All rights reserved.
PY - 2021
Y1 - 2021
N2 - This paper investigated two-dimensional spatial and temporal images of a copper emission line in laser-induced breakdown spectroscopy (LIBS), in order to clarify the excitation/de-excitation processes occurring in a laser-induced plasma. The measurements were carried out under different plasma gases (argon, krypton, helium, and nitrogen), pressure levels (100 – 900 Pa) and delay times (100 – 1000 ns) with the aim of monitoring their effects on the behavior of the copper emission. Depending on the plasma gas type and the pressure level, large differences were found in the plasma shape and temporal intensity evolution of the copper emission profile. Namely, krypton produced the most compact plasma emitting larger intensities, compared to argon and helium, and an increase in the gas pressure made these plasmas to shrink, which could be related principally to the stopping power of the applied gases. Through temporally resolved analysis, the delay profiles could be obtained for each plasma gas, indicating that the helium plasma disappeared more rapidly than the argon and krypton plasmas. It was suggested that the variations in the emission intensity would be determined by interactions between gas particles and highly energetic particles in the plasma breakdown as well as interactions between excited gas particles and copper species during plasma expansion. These insights could prove to be useful in the understanding of the background of LIBS as well as the optimization of its practical applications.
AB - This paper investigated two-dimensional spatial and temporal images of a copper emission line in laser-induced breakdown spectroscopy (LIBS), in order to clarify the excitation/de-excitation processes occurring in a laser-induced plasma. The measurements were carried out under different plasma gases (argon, krypton, helium, and nitrogen), pressure levels (100 – 900 Pa) and delay times (100 – 1000 ns) with the aim of monitoring their effects on the behavior of the copper emission. Depending on the plasma gas type and the pressure level, large differences were found in the plasma shape and temporal intensity evolution of the copper emission profile. Namely, krypton produced the most compact plasma emitting larger intensities, compared to argon and helium, and an increase in the gas pressure made these plasmas to shrink, which could be related principally to the stopping power of the applied gases. Through temporally resolved analysis, the delay profiles could be obtained for each plasma gas, indicating that the helium plasma disappeared more rapidly than the argon and krypton plasmas. It was suggested that the variations in the emission intensity would be determined by interactions between gas particles and highly energetic particles in the plasma breakdown as well as interactions between excited gas particles and copper species during plasma expansion. These insights could prove to be useful in the understanding of the background of LIBS as well as the optimization of its practical applications.
KW - Laser-induced breakdown spectrometry
KW - copper emission lines
KW - excitation mechanism
KW - time-resolved measurement
KW - two-dimensional imaging
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U2 - 10.2116/ANALSCI.20P203
DO - 10.2116/ANALSCI.20P203
M3 - Article
C2 - 33100304
AN - SCOPUS:85101520931
VL - 37
SP - 367
EP - 375
JO - Analytical Sciences
JF - Analytical Sciences
SN - 0910-6340
IS - 2
ER -