LIBS principles:

A short (some nanoseconds or shorter) and high intensity laser pulse (mJ-hundreds of mJ) is focused on a sample, a small amount of material is ablated and a plasma plume is formed with temperature of about 10000-20000 Kelvin. At this temperature, the molecules and atoms dissociate into excited atomic species. After some nanosecond/microseconds the atomic species recombine and emit light at characteristic wavelengths. The emitted light is usually collected using a high resolution spectrometer. These emission lines reflect the electron structure of each atom and are thus a fingerprint of the atoms which are present in the sample. The identification of the measured lines using available material libraries combined with the line intensities allows determination of the concentration of the atomic species in the sample.

SINTEF facilities:

Andor spectrometer and YAG laser

SINTEF LIBS facilities include a Q-Switch YAG laser from Quantel emitting pulses @ 1064, 532 and 266 nm and a Mechelle spectrometer from Andor equipped with an Intensified CCD camera. The pulse durations of the laser are 4 nanoseconds and the energy ranges from 400 mJ @ 1064 nm to 30 mJ @ 266 nm. The Andor spectrometer allows acquisition of spectra in the 200-900 nm spectral window with sub nanometre resolution. The Intensified CCD camera includes also a digital delay generator, for low-light imaging applications requiring fast gating (gates ranging from 50 ns to 20 s and delays ranging from 25 ps to 20 s with 25 ps resolution). Our lab is also equipped with other more conventional lasers and spectrometers

Advantage of LIBS:

• All the chemical elements can be detected
• Less/reduced needs for sample preparation
• Can be applied to solid, liquid and gaseous sample
• Small amounts of material are consumed during the analysis

Typical LIBS application:

• Identification of metal samples in sorting application, analysis of metal alloy, analysis of carbon in steel
• Identification of heavy metals in polluted environment, air, liquid (water mud) or polluted soil. Analysis of lead in wall paint, etc…
• Analysis of metal composition in art paint
• One line diagnostic methods for metal species in combustion process (process gaz, gas emission)
• Quantitative analysis of aerosols
• Environmental and forensic application

Other possible spectroscopy techniques available with SINTEF LIBS facilities:

The Andor spectrometer is very well suited for applications where very fast time resolved measurements (nanosecond precision) and high wavelength resolution (sub nanometre) are necessary. Examples of useful and interesting applications include spectroscopic measurements of fast chemical or physical processes (fast chemical reactions) and spectroscopy of plasma plume or flame for process monitoring or surveillance. The Intensified CCD camera can also be used alone for low light level imaging application.

Combined with the YAG laser or other pulsed source it is also well suited for Laser Induced Fluorescence spectroscopy or for classical fluorescence spectroscopic techniques. The YAG laser can also be used for non linear spectroscopy or for measurement of non linear properties of materials.