Laser Induced
Breakdown
Spectroscopy (LIBS) is a rapid, remote, elemental analysis tool for
planetary
science. LIBS uses a laser pulse focused on a surface to ablate a
small amount of material. Atoms ablated in ionized or excited
states
emit light, yielding the characteristic emission of lines of the
elements
present in the material (See
video
clips of the LIBS process). Spectral analysis and comparison
with calibrated
standards yields quantitative elemental compositions. The
following
features make LIBS especially atractive for planetary surface analysis:
- Rapid elemental analysis-- one measurement/ laser pulse, or average spectra from multiple laser pulses for greater accuracy in <2 minutes
- Detects all elements--high and low z
- Low Detection Limits--element specific, ranging from 2-1000 ppm for most elements
- Point Detection Capability even at stand-off distances (~1mm spot size)
- Samples can be analyzed at distances up to 20 meters from instrument
- Far more rapid data acquisition than in-situ techniques
- Can sample over otherwise inaccessible terrain, on cliff faces, etc.
- Repeated laser pulses at the same spot can remove dust or weathering layers to allow analysis of underlying rock
These advantages
make
LIBS a totally unique instrument: It it the only instrument that
can determine the elemental compositions
of dust-covered rocks
remotely. The typical remote-sensing rover-based instruments-
imaging
and reflection spectroscopy- can be rendered useless for determining
rock
compositions when the dust covering is more than a few microns.
LIBS
is the only instrument that can be trusted to accurately
identify
rocks remotely in many typical planetary surface environments!
