Laser-induced breakdown spectroscopy (LIBS) is a direct and versatile analytical technique that performs the elemental composition analysis based on optical emission produced by laser induced-plasma, with a little or no sample preparation. The performance of the LIBS technique relies on the choice of experimental conditions which must be thoroughly explored and optimized for each application. The main parameters affecting the LIBS performance are the laser energy, laser wavelength, pulse duration, gate delay, geometrical set-up of the focusing and collecting optics. In LIBS quantitative analysis, the gate delay and laser energy are very important parameters that have pronounced impact on the accuracy of the elemental composition information of the materials. The determination of calcium elements in the pelletized samples was investigated and served for the purpose of optimizing the gate delay and laser energy by studying and analyzing the results from emission intensities collected and signal to background ratio (S/B) for the specified wavelengths.

Laser-plasma interaction; Emission of electromagnetic radiation; Thermodynamics of plasma;INDUCED BREAKDOWN SPECTROSCOPY; CARBON; ARGON; LIBS; AIR

In this study, graphite laser induced plasma dynamics are investigated by optical emission spectroscopy. Graphite plasma is generated using a 1064 nm Nd: YAG laser in helium environment under different ambient pressures. Characteristics of graphite spectra as lines intensity variations and signal to noise ratio are presented with main focus on the influence of the helium environment and pressure on plasma dynamics. Carbon atomic emission lines are used to study the dynamical behavior of plasma such as the excitation temperature and electron density to describe emission differences in different ambient conditions. The excitation temperature and plasma electron density are the primary factor contribute to the differences among the atomic carbon emission in different ambient pressures.

INDUCED BREAKDOWN SPECTROSCOPY; LIBS; SAMPLES

In this study, Nd: YAG laser pulse is used to ablate the Magnesium sample for laser induced breakdown spectroscopy analysis. The emission lines are plotted for ionic and atomic element of Mg I and Mg II respectively. The emission lines of Mg I and Mg II were recorded at wavelength of 279.55 nm, 280.27 nm and 285.21 nm. The analysis including the different of gate delay, determination of signal to background ratio and calibration curve of different concentration of magnesium is discussed in details.

Recent developments in Laser Induced Breakdown Spectroscopy (LIBS) instrumentation allow the acquisition of several spectra in a second. The dataset from a typical LIBS experiment can consist of a few thousands of spectra. To extract the useful information from that dataset is painstaking effort and time consuming process. Most of the currently available softwares for spectral data analysis are expensive and used for offline data analysis. LabVIEW software compatible with spectrometer (in this case Ocean Optics Maya pro spectrometer), can be used to for data acquisition and real time analysis. In the present work, a LabVIEW based automated system for real-time LIBS analysis integrated with spectrometer device is developed. This system is capable of performing real time analysis based on as-acquired LIBS spectra. Here, we have demonstrated the LIBS data acquisition and real time calculations of plasma temperature and electron density. Data plots and variations in spectral intensity in response to laser energy were observed on LabVIEW monitor interface. Routine laboratory samples of brass and calcine bone were utilized in this experiment. Developed program has shown impressive performance in real time data acquisition and analysis.

laser-induced plasma; plasma spectroscopy; zinc; manganese; gate delay; calibration curve; normalization;INDUCED BREAKDOWN SPECTROSCOPY; FORENSIC ANALYSIS; SELF-ABSORPTION; EMISSION; LIBS; SPECTROMETRY; ABLATION; INKS

Laser-induced plasma spectroscopy is performed to determine the elemental compositions of manganese and zinc in potassium bromide (KBr) matrix. This work has utilized Q-switched Nd: YAG laser installed in LIBS2500plus system at fundamental wavelength. The pelletized sample were ablated in air with maximum laser energy of 650 mJ for different gate delays ranging from 0-18 mu s. The spectra of samples are obtained for five different compositions containing preferred spectral lines. The intensity of spectral line is observed at its maximum at a gate-delay 0.83 mu s and subsequently decayed exponentially with the increasing of gate delay. Maximum signal-to-background ratio of Mn and Zn were found at gate delays of 7.92 and 7.50 mu s, respectively. Initial calibration curves show bad data fitting, whereas the locally normalized intensity for both spectral lines shows enhancement since it is more linearly regressed. This study will give a better understanding in studying the plasma emission and the spectra analysis.

laser-induced plasma breakdown; calcium; calibration curves; localized normalization;PLASMA-MASS SPECTROMETRY; MOLECULAR-EMISSION; LIBS; AIR; TEMPERATURE; SPECTRA

This paper focuses on localized normalization for improved calibration curves in laser-induced breakdown spectroscopy (LIBS) measurements. The calibration curves have been obtained using five samples consisting of different concentrations of calcium (Ca) in potassium bromide (KBr) matrix. The work has utilized Q-switched Nd: YAG laser installed in LIBS2500plus system with fundamental wavelength and laser energy of 650 mJ. Optimization of gate delay can be obtained from signal-to-background ratio (SBR) of Ca II 315.9 and 317.9 nm. The optimum conditions are determined in which having high spectral intensity and SBR. The highest spectral lines of ionic and emission lines of Ca at gate delay of 0.83 mu s. From SBR, the optimized gate delay is at 5.42 mu s for both Ca II spectral lines. Calibration curves consist of three parts; original intensity from LIBS experimentation, normalization and localized normalization of the spectral line intensity. The R-2 values of the calibration curves plotted using locally normalized intensities of Ca I 610.3, 612.2 and 616.2 nm spectral lines are 0.96329, 0.97042, and 0.96131, respectively. The enhancement from calibration curves using the regression coefficient allows more accurate analysis in LIBS.