Detection of Uranium Using Laser-Induced Breakdown Spectroscopy

Emissions from a laser-induced breakdown spectroscopy (LIBS) plasma were examined in the region from 750 nm to 2000 nm. A Nd:YAG laser at 532 nm and 75 mJ per pulse were used to initiate the plasma. The detector was an InGaAs 1024 element diode array cooled to -100 degrees C. An f/4 spectrometer with gratings blazed for this region was used as the dispersive element. Survey spectra of soils, uranium, and other selected samples were taken in air and in a flow cell purged with argon at a local pressure of 0.84 x 10(5) Pa. Strong infrared lines of neutral aluminum, carbon, potassium, silicon, sulfur, and uranium, as well as once ionized lines of calcium, were observed out to 1670 nm. For potassium, the detection limits of the infrared (IR) system were compared with those obtained from a standard intensified charge-coupled device (ICCD) spectrometer arrangement, using the 766-770 nm doublet. Detection limits with the IR system were twice as high as those obtained from the ICCD detector.

High-performance ion chromatographic separation of uranium and thorium in natural waters and geological materials

A hand-held device for laser-induced breakdown spectroscopy has been investigated for the determination of uranyl fluoride surface contamination. This research demonstrates the ability to successfully detect uranium on surfaces when using a low resolving power (λ/Δλ=4000) spectrograph, with a 5 mJ energy per 1 ns pulsed laser radiation, available as a commercially packaged hand-held system. Sand/uranyl fluoride mixtures are prepared to simulate residue likely encountered during decontamination efforts at facilities that handle uranium hexafluoride. Detection limits are described for four uranium lines with one revealing the capability to detect uranium at a level of 250 parts per million. Advantages of the studied compact device include that location specific information can be obtained on-site to augment contamination identification.

Laser-induced breakdown spectroscopy of uranium in the vacuum ultraviolet range

We developed a stand-off laser-induced breakdown system for the remote detection of nuclear materials. Ce, a Pu surrogate, in pellets with KCl matrix was detected by this system in open path and through shielding windows.

Nuclear threat detection remains a vital global security concern, particularly in environments requiring real-time, non-contact monitoring. This study presents a remote detection system that combines laser-induced breakdown spectroscopy (LIBS), machine learning, and wireless signal optimization to detect uranium and plutonium from distances of 30 to 70 meters. The DRUP-LIBS system utilizes both multi- and single-wavelength laser pulses to generate actinide-specific plasma emissions, which are analyzed using artificial intelligence with 100% classification accuracy. Wireless modules equipped with directional antennas maintained signal quality over long distances. Plasma temperature and electron density were measured using Boltzmann plots and Stark broadening, confirming plasma consistency. Results show that the system reliably distinguishes between uranium and plutonium, with plutonium exhibiting stronger emissions and higher electron density. These findings support DRUP-LIBS as a secure, non-intrusive tool for real-time radioactive threat detection in open environments.

Direct determination of uranium in the concentration range of 8 μg L−1 to mg L−1 in water samples originating from different geochemical environments has been done using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Uranium detection with 2–3% RSD (relative standard deviation) has been achieved in water samples by optimizing the plasma power, argon and sheath gas flow. These parameters were optimized for three different emission lines of uranium at 385.958, 409.014 and 424.167 nm. Interference arising due to the variation in concentration of bicarbonate, sodium chloride, calcium chloride, Fe and dissolved organic carbon (DOC) on the determination of uranium in water samples was also cheeked as these are the elements which vary as per the prevailing geochemical environment in groundwater samples. The concentration of NaHCO3, CaCl2 and NaCl in water was varied in the range 0.5–2.0%; whereas Fe ranged between 1 and 10 μg mL−1 and DOC between 0.1–1%. No marked interference in quantitative determination of uranium was observed due to elevated level of NaHCO3, CaCl2 and NaCl and Fe and DOC in groundwater samples. Concentration of uranium was also determined by other techniques like adsorptive striping voltametry (AdSv); laser fluorimetry and alpha spectrometry. Results indicate distinct advantage for uranium determination by ICP-OES compare to other techniques.

Dual-pulse laser induced breakdown spectroscopy: Time-resolved transmission and spectral measurements

The laser-ablation threshold of aluminum alloy was accurately measured by dual-wavelength dual-pulse laser-ablation laser-induced breakdown spectroscopy under orthogonal geometric arrangement. For 532 nm laser wavelength and 12 ns laser pulse width, the laser-ablation energy threshold of aluminum alloy was determined to be 48 J, equivalent with a fluence threshold of 9.8 J/cm2, under tightly focused condition with an aspheric lens of 2 cm focal length. This is a new spectroscopic method to measure laser-ablation threshold. It is more sensitive and more accurate in comparison with established methods for laser-ablation threshold measurement, and the measurement is rapid and quite convenient. This method can be used for accurate laser-ablation threshold measurement for different materials.