Effects of Microwave-Enhanced Plasma on Laser Ignition

Hayashi, Jun; Liu, Chen; Akamatsu, Fumiteru; Nishiyama, Atsushi; Moon, Ahsa; Ikeda, Yuji

doi:10.1007/978-3-319-45504-4_14

Cited by 2 publications

(2 citation statements)

References 16 publications

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“…We previously reported on the application of pulsed microwave to laser-induced breakdown spectroscopy (LIBS), with breakthrough enhancements in plasma size and lifetime of air and gas mixtures [5][6][7][8], and a major increase in the emission signals of solid targets, such as Al 2 O 3 [9]. Applications of the MW-LIBS to Zr, Gd, wet Zr, and Mg were also presented [10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Antenna Characteristics of Helical Coil with 2.45 GHz Semiconductor Microwave for Microwave-Enhanced Laser-Induced Breakdown Spectroscopy (MW-LIBS)

Ikeda¹,

Hirata²,

Soriano³

et al. 2022

Materials

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A copper helical coil antenna was developed, characterized, and optimized for 2.45 GHz operations supplied by a microwave semiconductor oscillator. The application field of interest is laser-induced breakdown spectroscopy enhanced by microwave. Simulations using the Ansys HFSS demonstrate the superior localized E-field strength of the helical coil antenna, compared with other antenna-type structures. Simulation results show that E-field strength at the tip of the antenna has a logarithmic trend for increasing the coil pitch. The optimum pitch is 5 mm for a coil diameter of 6.5 mm upon consideration of the system compactness. Despite the antenna’s open-circuit end, the presence of target samples does not interfere with the E-field and H-field distribution of the antenna and the surrounding environment. Applications in microwave-enhanced laser-induced breakdown spectroscopy (MWLIBS) confirm the importance of the antenna reflector. The electric field strength was over 100 times higher than the previous capacitor-like antenna. The antenna configuration angle was then experimentally optimized for maximum enhancement effects in the spectrochemical analysis of Al2O3. The antenna angle of 60° from the laser beam propagation achieved maximum enhancement in the emission signal of Al I.

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Section: Introductionmentioning

confidence: 99%

Antenna Characteristics of Helical Coil with 2.45 GHz Semiconductor Microwave for Microwave-Enhanced Laser-Induced Breakdown Spectroscopy (MW-LIBS)

Ikeda¹,

Hirata²,

Soriano³

et al. 2022

Materials

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“…However, ablation plasmas are typically limited in their expansion due to system constraints, such as volume size change and plasma lifetime 21 , limitations that are being addressed by microwave-enhanced LIBS by combining microwaves and pulsed lasers resulting in a significantly improved performance of the system [21][22][23][24][25][26][27][28][29][30][31][32] . The emission intensity of the plasma is significantly enhanced by microwave superposition because microwave energy can sustain the plasma for a much longer period, allowing for more emission events to occur 15,22,31,[33][34][35][36][37][38][39][40][41][42][43][44][45][46] . In addition, the spatial volume of the plasma is expanded by two orders of magnitude, which further increases the amount of light emitted and detected by the system.…”

mentioning

confidence: 99%

Laser ablation plasma expansion using microwaves

Ikeda,

Soriano,

Ohba

et al. 2023

Sci Rep

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This study explores the potential of utilizing microwaves to sustain the expansion of transient laser ablation plasma of Zr target. By application of microwaves on the plasma, we observe a significant enhancement with a two to three order of magnitude increase in the plasma emission intensity, and 18 times increase in the plasma’s spatial volume. We investigate the temperature change of the plasma and observe that it decreases from 10,000 K to approximately 3000 K. Electron temperature decreased with volume expansion owing to increased surrounding air interaction, while the plasma can be sustained in air using microwaves. The increase in electron temperature during temperature drop is indicative of non-equilibrium plasma. Our results emphasize the contribution of microwaves in promoting enhanced emission and plasma formation at controlled, low temperature, thereby demonstrating the potential of microwaves to enhance the accuracy and performance of laser-induced breakdown spectroscopy. Importantly, our study suggests that microwaves could also mitigate the generation of toxic fumes and dust during ablation, a critical benefit when handling hazardous materials. The system we've developed is highly valuable for a range of applications, notably including the potential to reduce the possible emergence of toxic fumes during the decommissioning of nuclear debris.

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Effects of Microwave-Enhanced Plasma on Laser Ignition

Cited by 2 publications

References 16 publications

Antenna Characteristics of Helical Coil with 2.45 GHz Semiconductor Microwave for Microwave-Enhanced Laser-Induced Breakdown Spectroscopy (MW-LIBS)

Antenna Characteristics of Helical Coil with 2.45 GHz Semiconductor Microwave for Microwave-Enhanced Laser-Induced Breakdown Spectroscopy (MW-LIBS)

Laser ablation plasma expansion using microwaves

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