Formation of 238U16O and 238U18O observed by time-resolved emission spectroscopy subsequent to laser ablation

Abstract

We have measured vibronic emission spectra of an oxide of uranium formed after laser ablation of the metal in gaseous oxygen. Specifically, we have measured the time-dependent relative intensity of a band located at approximately 593.6 nm in 16O2. This band grew in intensity relative to neighboring atomic features as a function time in an oxygen environment but was relatively invariant with time in argon. In addition, we have measured the spectral shift of this band in an 18O2 atmosphere. Based on this shift, and by comparison with earlier results obtained from free-jet expansion and laser excitation, we can confirm that the oxide in question is UO, consistent with recent reports based on laser ablation in 16O2 only.

Gas Phase Chemical Evolution of Uranium, Aluminum, and Iron Oxides

“…spectral line widths of 10 pm) to differentiate 238 U from 235 U and thus to determine the uranium enrichment level 32 . Another recent study 33 used different oxygen isotopes ( 16 O and 18 O) to unambiguously identify the emission feature observed in laser ablation studies at ~593.6 nm as due to UO specifically. In the current study, we used this spectral data as a reference to compare the strong emission intensities of the uranium atom at 591.5 nm with the uranium monoxide emission centered at 593.6 nm.…”

Remote Detection of Uranium Using Self-Focusing Intense Femtosecond Laser Pulses

“…Laser-induced breakdown spectroscopy (LIBS) represents a robust method for in-situ, remote, and real-time analytical measurements of material composition [5][6][7]. This method has demonstrated its high versatility in extraterrestrial [8] and deep-sea exploration [9], detection and classification of explosives [10,11], analysis of soil contaminants [12], use in nuclear power plants and dry cask storage systems [13][14][15], and detection of nuclear materials in general [16][17][18]. LIBS relies on focusing a high-power laser pulse onto the surface of a sample to produce ablation and, subsequently, a plasma.…”

Laser-produced uranium plasma characterization and Stark broadening measurements

“…For example, in nuclear forensics analysis, it is desired to characterize the material and infer its origin and production history based upon the elemental and isotopic composition. Laser ablation (LA)-based techniques have been demonstrated in this context [1][2][3][4][5][6][7][8][9][10][11] and shown to exhibit several attractive characteristics, including little to no sample preparation, applicability to a wide range of materials, no requirement of specific sample dimensions, real-time capability, high sensitivity, and feasibility of remote analysis. 12 LA-optical emission spectroscopy (LA-OES), often referred to as laser-induced breakdown spectroscopy (LIBS), is a powerful technique whereby optical emission from a laserinduced plasma (LIP) is resolved spectrally.…”

“…Spectral simulation may aid toward deeper understanding and deconvolution of underlying oxide spectral features from ionic or atomic emission in the plasma, for example, for U plasmas in which U oxide emission is significant and makes the plasma diagnostics more challenging. 11,22,33 In this work, we assess the validity of equilibrium assumptions in the U LIP under reduced pressure conditions in order to determine the plasma properties, namely, T e and N e and report the Stark broadening parameters of U II 500.82 nm and U I 499.01 nm transitions.…”