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100 m fiber-coupled microchip laser-induced breakdown spectroscopy for remote elemental analysis applicationsBatsaikhan, M.; 大場 弘則; 若井田 育夫
Optics Express (Internet), 32(25), p.45158 - 45170, 2024/12
被引用回数：1 パーセンタイル：27.60(Optics)This study aims to develop ultralong fiber optic cable (FOC) coupled microchip laser-induced breakdown spectroscopy (mLIBS) to reveal the elemental distribution and local composition of nuclear fuel debris in an accident-damaged reactors at Fukushima Daiichi Nuclear Power Station (FDNPS). Currently at FDNPS, the distance between the area where humans can safely work in a sufficient space and the nuclear fuel debris is expected to be over 100 m. Therefore, it becomes crucial to analyze the light transmittance performance of FOC-coupled mLIBS systems over such long distances in a high-radiation environment. We found that compared with an FOC with low-OH groups, that with high-OH groups exhibits better light transmittance performance. The maximum FOC length for microchip crystal oscillation is estimated to be longer than 800 m, although attenuation is observed with the increase in FOC length. Quantitative analysis of Gd is successfully performed in the visible region using the mLIBS system coupled with up to 300 m-long FOCs, with the limits of detection being between 0.1% and 0.2%.
Batsaikhan, M.; 大場 弘則; 狩野 貴宏; 赤岡 克昭; 若井田 育夫
Optics Express (Internet), 32(24), p.42624 - 42638, 2024/11
被引用回数：0 パーセンタイル：0.00(Optics)A fiber-coupled, acoustic-wave-assisted microchip laser-induced breakdown spectroscopy system (AW-mLIBS) was developed to analyze the elemental composition and surface imaging. In this study, we measured the dependence of sample temperature and laser ablation angle on the laser-induced plasma-optical emission and LIP-acoustic signal. The intensity of the laser-induced plasma-optical emission and ablated mass at three different temperatures and eight different laser ablation angles were estimated using a zirconium sample. Simultaneously, we investigated the laser-induced plasma-acoustic signal amplitude, propagation speed, and shape by synchronizing the AW-mLIBS system with a high-speed camera. The results revealed that the laser-induced plasma-optical emission increases with increasing temperature and is unaffected by laser ablation angle up to 40 degree because the amount of the ablated mass was similar and the plasma. Additionally, no considerable variation in plasma temperature obtained using the Boltzmann method over the sample temperature. However, the propagation speed of the laser-induced plasma-acoustic signal differs with temperature but has marginal angular dependence because the laser-induced plasma-acoustic signal propagates as semispherical. Furthermore, small and no considerable changes observed in the laser-induced plasma-acoustic signal amplitude up to 100 degree Celsius, and the laser ablation angle showed a similar tendency to that of the laser-induced plasma-optical emission.
Batsaikhan, M.
no journal, ,
A fiber-coupled, acoustic wave assisted (AW) microchip laser induced breakdown spectroscopy (mLIBS) system is a promising tool for remote and on-site analysis of nuclear fuel debris formed in damaged reactor vessels at Fukushima Daiichi Nuclear Power Station. In the AW-mLIBS system, the laser induced plasma optical emission is used to measure the sample's elemental composition. The acoustic signal is recorded as an auxiliary source of information for optimizing the lens-to-sample distance and visualizing the sample's surface. The currently available data regarding fuel debris's elemental composition, distribution, shape, and size are still limited. These fuel debris data are crucial to deciding further strategies and decommissioning steps for the FDNPS. Additionally, a temperature gradient exists in the reactor vessels owing to the decay heat of the nuclear fuel debris. Therefore, investigating the effect of sample temperature and laser ablation angle (LAA) is crucial to adapt the system to in-situ measurements This talk will discuss the dependence of sample temperature and LAA on the laser-induced plasma-optical emission and LIP-acoustic signal for zirconium metal, which is a part of fuel debris.
