Laser-Induced Breakdown Spectroscopy
Laser-induced breakdown spectroscopy (LIBS) is a type of atomic emission spectroscopy which uses a highly energetic laser pulse as the excitation source.
The laser is focused to form a plasma, which atomizes and excites samples.
The formation of the plasma only begins when the focused laser achieves a certain threshold for optical breakdown, which generally depends on the environment and the target material.
How does LIBS work?
The main physical process that forms the essence of LIBS technology is the formation of high-temperature plasma, induced by a short laser pulse.
When the short-pulse laser beam is focused onto the sample surface, a small volume of the sample mass is ablated (i.e. removed via both thermal and non-thermal mechanisms) — in a process known as Laser Ablation.
This ablated mass further interacts with a trailing portion of the laser pulse to form a highly energetic plasma that contains free electronics, excited atoms and ions.
When the laser pulse terminates, the plasma starts to cool.
During the plasma cooling process, the electrons of the atoms and ions at the excited electronic states fall down into natural ground states, causing the plasma to emit light with discrete spectral peaks.
The emitted light from the plasma is collected and coupled with an ICCD/spectrograph detector module for LIBS spectral analysis.
Each element in the periodic table is associated with unique LIBS spectral peaks.
By identifying different peaks for the analyzed samples, its chemical composition can be rapidly determined.
Often, information on LIBS peak intensities can be used to quantify the concentration of trace and major elements in the sample.
With the advancement of powerful chemometric software for LIBS data analysis, and with steady progress in understanding laser ablation fundamentals, today’s analytical researchers are applying LIBS effectively for both quantitative and material discriminatory analysis for a wide range of sample matrices.
Why it is in news?
Pragyan, the rover of the Chandrayaan-3 mission, has confirmed the presence of sulphur on the moon’s surface, near its south pole, and is still searching for hydrogen.
The Laser-Induced Breakdown Spectroscopy (LIBS) instrument aboard the rover has made the first-ever in-situ measurements on the elemental composition of the lunar surface near the south pole.
Preliminary analyses have unveiled the presence of Aluminum (Al), Sulphur (S), Calcium (Ca), Iron (Fe), Chromium (Cr), and Titanium (Ti) on the lunar surface. Further measurements have revealed the presence of manganese (Mn), silicon (Si), and oxygen (O).
Thorough investigation regarding the presence of Hydrogen is under way.
COMMENTS