Analysis of gadolinium oxide using microwave-enhanced fiber-coupled micro-laser-induced breakdown spectroscopy

Abstract

We report on the analysis of pure gadolinium oxide (Gd2O3) and its detection when mixed in surrogate nuclear debris using microwave-enhanced fiber-coupled micro-laser-induced breakdown spectroscopy (MWE-FC-MLIBS). The target application is remote analysis of nuclear debris containing uranium (U) inside the Fukushima Daiichi Nuclear Power Station. The surrogate nuclear debris used in this study contained gadolinium (Gd), cerium (Ce), zirconium (Zr), and iron (Fe). Ce is a surrogate for U, and Gd2O3 is an excellent hazard index because it is incorporated into some fuel rods. Gd detection is essential for assessing debris prior to the retrieval process. Surrogate debris was ablated by an 849 ps 1064 nm micro-laser under atmospheric pressure conditions while a helical antenna propagated 2.45 GHz 1.0 kW microwaves for 1.0 ms into the laser ablation, which was then characterized by a high-speed camera and high-resolution spectrometers. The results showed that microwave-induced plasma expansion led to enhanced emission signals of Gd I, Zr I, Fe I, Ce I, and Ce II. No self-absorption of Gd emissions was evident from the detection limit calibration graphs. Moreover, microwave irradiation decreased the standard deviations of the Gd and Ce emissions and lowered the Gd detection limit by 60%.

Plasma emission intensity expansion of Zr metal and Zr oxide via microwave enhancement laser-induced breakdown spectroscopy

“…where I i is the emission, A i is the transition probability, g u,i is the statistical weight, E u,i is the ionization potential, S(T) is the partition function, T is the excitation temperature, and k is Boltzmann's constant. The Saha-Boltzmann method was used for the ionization degree 15,16…”

“…To compensate for the reduction in plasma emission intensity and signal-to-noise ratio (SNR) caused by radiation effects and long-distance operation, emission intensities were enhanced using microwaves in LIBS. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] The feasibility of microwave enhancement has been demonstrated for alumina, lead, zirconium (Zr) metal, gadolinium pure solids, gadolinium compressed powder mixtures, and stainless steel, resulting in an increased SNR of almost three orders of magnitude. [16][17][18][19][20][21][22][23][24] We also reported enhancements in the volume and plasma lifetime without increasing the size of the ablation crater, which is essential for reducing toxic fumes.…”

“…[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] The feasibility of microwave enhancement has been demonstrated for alumina, lead, zirconium (Zr) metal, gadolinium pure solids, gadolinium compressed powder mixtures, and stainless steel, resulting in an increased SNR of almost three orders of magnitude. [16][17][18][19][20][21][22][23][24] We also reported enhancements in the volume and plasma lifetime without increasing the size of the ablation crater, which is essential for reducing toxic fumes. 18 Furthermore, the sustained expansion of the plasma in space was easily controlled for the duration of microwave energy.…”

Simultaneous analysis of gadolinium and surface imaging using a fiber-coupled acoustic wave-assisted microchip LIBS system

“…In this system, the FC-mLIBS system was extended to coupling with a microwave source and helical coil antenna to enhance the LIBS emission signal. 24–26…”

Detection of zinc in pig feed based on the cavities of different shapes combined with LIBS

“…However, the detection sensitivity of this technique is low, detection limit is high, and its application in the detection of trace elements is limited. The researchers have developed various methods for enhancing the LIBS signal, such as double-pulse LIBS [13], spark discharge assisted LIBS [14], nanoparticles LIBS [15], microwaveassisted LIBS [16], and magnetic field confinement LIBS…”