title: A Comparative Study of Single-pulse and Double-pulse Laser-Induced Breakdown Spectroscopy with Uranium-containing Samples.
abstract: Laser-induced breakdown spectroscopy (LIBS) holds potential advantages in special nuclear material (SNM) sensing and nuclear forensics, which require rapid analysis, minimal sample preparation, and stand-off distance capability. SNM, such as U, however, result in crowded emission spectra with LIBS, and characteristic emission lines are challenging to discern. It is well-known that double-pulse LIBS (DPLIBS) improves the signal intensity for analytes over conventional single-pulse LIBS (SPLIBS). This study investigates the U signal in a glass matrix using DPLIBS and compares it to signal obtained using SPLIBS. Double-pulse LIBS involves sequential firing of a 1.06 µm Nd:YAG pre-pulse and 10.6 µm TEA CO2 heating pulse in a near collinear geometry. Optimization of experimental parameters including inter-pulse delay and energy follows identification of characteristic lines for the bulk analyte Ca and the minor constituent analyte U for both DPLIBS and SPLIBS. Spatial and temporal coupling of the two pulses in the proposed DPLIBS technique yields improvements in analytical merits with a negligible increase in damage to the sample compared to SPLIBS. Subsequently, the study discusses optimum plasma emission conditions of U lines and relative figures of merit in both SPLIBS and DPLIBS. Investigation into plasma characteristics also addresses plausible mechanisms related to the observed U analyte signal variation between SPLIBS and DPLIBS.
authors.affiliation: Center for Materials Under Extreme Environment (CMUXE), School of Nuclear Engineering Purdue University, West Lafayette, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Skrodzki
authors.affiliation: Center for Materials Under Extreme Environment (CMUXE), School of Nuclear Engineering Purdue University, West Lafayette, USA.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Becker
authors.affiliation: Center for Materials Under Extreme Environment (CMUXE), School of Nuclear Engineering Purdue University, West Lafayette, USA pdiwakar@purdue.edu.
authors.forename: Prasoon K
authors.initials: PK
authors.lastname: Diwakar
authors.affiliation: Pacific Northwest National Laboratory, Richland, USA.
authors.forename: Sivanandan S
authors.initials: SS
authors.lastname: Harilal
authors.affiliation: Center for Materials Under Extreme Environment (CMUXE), School of Nuclear Engineering Purdue University, West Lafayette, USA.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Hassanein
keywords: DPLIBS; Double-pulse laser-induced breakdown spectroscopy; Nuclear forensics; Plasma diagnostics; Signal enhancement; Uranium