Improved Analysis of Manganese in Steel Samples Using Collinear Long–Short Double Pulse Laser-Induced Breakdown Spectroscopy (LIBS)

Abstract

A long-short double pulse laser-induced breakdown spectroscopy (long-short DP-LIBS) method was employed to improve the analytical performance of LIBS for the measurement of manganese in steel samples. The long pulse with a duration of 60 μs was generated using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser which was operated at free-running (FR) mode. To investigate the detection ability without sample preparation, the steel washers were tested using single-pulse LIBS (SP-LIBS) and long-short DP-LIBS, respectively. The measurement results show that long-short DP-LIBS was able to record clear spectra from the steel washers with a surface layer. Through the observation on the laser craters with a scanning electron microscope (SEM), the results suggest that the improvement in detection ability can be attributed to the pre-irradiation effect of long-pulse laser beam. Next, the analytical performance for quantitative measurement of manganese was evaluated employing ten standard steel samples. The results show that the linearity fit (R) of the calibration curve is 0.988 for long-short DP-LIBS, whereas, R is only 0.810 for SP-LIBS under the same measurement conditions. The repeated measurement results show that the average relative standard deviation (RSD) of the tested samples is 29.3% for SP-LIBS and is 10.5% for long-short DP-LIBS. The prediction results also show that the average relative error of prediction (REP) is 94.9% for SP-LIBS and is 4.9% for long-short DP-LIBS.

Improving the Detection Sensitivity for Laser-Induced Breakdown Spectroscopy: A Review

“…The results showed that the R 2 of calibration curve was improved from 0.810 to 0.988 using long-short DP-LIBS compared to SP-LIBS. In addition, the RSD was reduced from 29.3% (SP-LIBS) to 10.5% (long-short DP-LIBS) [52].…”

Sample Temperature Effect on Steel Measurement Using SP-LIBS and Collinear Long-short DP-LIBS

“…Thus FR laser pulse has lower energy density which is not enough to produce an observable plasma emission. [25][26][27] A short pulse laser with wavelength of 1 064 nm, pulse width of 5-8 ns, pulse energy of 24.5 mJ and frequency of 10 Hz is generated by the Laser (LOTIS TII, LS-2134U). The reflected short pulse laser beam combined with the long pulse laser beam by polarization prism to realize the collinear long-short DP-LIBS.…”

“…Table 1 lists the elemental compositions of standard steel sample and the iron content was obtained by subtracting the other major elements. 27) The sample were heated to the specified temperature in the muffle furnace, and the muffle furnace was operated at the atmosphere environment. The sample temperature varied as 20°C, 300°C, 500°C and 700°C.…”

“…It demonstrated the feasibility and enhanced detection ability of long-short DP-LIBS method due to pre-heating and re-heating effects of long pulse. [25][26][27] In this paper, the collinear long-short DP-LIBS was employed to discuss the sample temperature effect on steel measurement for the improvement of LIBS technique. The standard steel sample with different sample temperature was measured by single pulse LIBS (SP-LIBS) and collinear long-short DP-LIBS respectively to systematically study the sample temperature effects for steel measurement.…”

Signal Improvement for Underwater Measurement of Metal Samples Using Collinear Long-Short Double-Pulse Laser Induced Breakdown Spectroscopy

“…The long and short double-pulse LIBS method was proposed by our group and it has been named as LS-DP-LIBS [28,29]. In previous studies [30,31], LS-DP-LIBS has been compared with SP-LIBS based on the measurement results in an air atmosphere. Those studies have demonstrated that the plasma is enhanced and stabilized by LS-DP-LIBS.…”