Approach to Detection in Laser-Induced Breakdown Spectroscopy

Abstract

Gated detection with intensified detectors, e.g., ICCDs, is today the accepted approach for detection of plasma emission in laser-induced breakdown spectroscopy (LIBS). However, these systems are more cost-intensive and less robust than nonintensified CCDs. The objective of this paper is to compare, both theoretically and experimentally, the performance of an intensified (ICCD) and nonintensified (CCD) detectors for detection of plasma emission in LIBS. The CCD is used in combination with a mechanical chopper, which blocks the early continuum radiation from the plasma. The detectors are attached sequentially to an echelle spectrometer under the same experimental conditions. The laser plasma is induced on a series of steel samples under atmospheric conditions. Our results indicate that there is no substantial difference in the performance of the CCD and ICCD. Signal-to-noise ratios and limits of detection achieved with the CCD for Si, Ni, Cr, Mo, Cu, and V in steel are comparable or even better than those obtained with the ICCD. This result is further confirmed by simulation of the plasma emission signal and the corresponding response of the detectors in the limit of quantum (photon) noise.

A critical review of recent progress in analytical laser-induced breakdown spectroscopy

“…linear CCD) or a gated (e.g. intensified CCD camera, or iCCD for short) detector is better in a LIBS setup [22,23]. It has been suggested that linear CCD spectrometers are more robust, and provide better S/N and sensitivity; however, their resolution is poorer in broadband configurations and they do not enable sub-μs gating.…”

A method for improving wavelet threshold denoising in laser-induced breakdown spectroscopy

“…1(a), a typical LIBS signal receiving system has three main parts, namely optical system, detector system and electronic system. In the initial optical system, a fundamental noise source is photon shot noise, which results from the random nature of photon emission [25]. Photon shot noise is random, with a Poisson distribution of the number of detected photons [26].…”

Analytical optimization of some parameters of a Laser-Induced Breakdown Spectroscopy experiment

“…This was qualitatively confirmed by the following simple phenomenological model describing the temporal evolution of the continuum intensity I cont =I C · exp(−t /τ C ) and of the line intensity I line =I L ·t · exp(−t /τ L ), where I C and I L are the intensities when the laser pulse reaches the sample at t = 0. This means that the Bremsstrahlung continuously decreases with time whereas the line intensity shows a maximum at a delay τ L [8][9][10][11][12]; then the SBR can be analytically calculated as:…”