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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.42626 - 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.; 赤岡 克昭; 佐伯 盛久*; 狩野 貴宏; 大場 弘則; 若井田 育夫
Journal of Nuclear Science and Technology, 61(5), p.658 - 670, 2024/05
被引用回数：2 パーセンタイル：43.92(Nuclear Science & Technology)この実験研究では、レーザー誘起ブレークダウン分光法(LIBS)を用いて模擬燃料デブリの二次元元素マッピングを実行し、サンプル表面の元素組成と分布を決定した。本物の燃料デブリはサンプルとして入手できないため、化合物や金属などの予測材料から模擬燃料デブリを作製した。Nd:YAGレーザーの第2高調波を使用して、サンプル表面にプラズマを生成させた。さらに、エシェル分光器を使用して、435
650nmの可視波長範囲でプラズマからの発光を検出した。収集されたデータセットのサイズと複雑さから従来のデータ分析方法では良い効果が得られないことが判明した。そのため本研究では、主成分分析や多変量曲線分解能代替最小二乗法などのラベルフリー化学測定法に基づく方法を実装して、サンプル内の各成分に関する空間情報およびスペクトル情報を取得した。結果として、LIBSと化学測定法の統合が、事前知識がほとんどまたは全く無くてもサンプル(燃料デブリなど)に関する定性情報を取得するための非常に効果的なツールであることを実証した。
Batsaikhan, M.; 大場 弘則; 狩野 貴宏; 赤岡 克昭; 若井田 育夫
Journal of Analytical Atomic Spectrometry, 39(2), p.423 - 432, 2024/02
被引用回数：3 パーセンタイル：49.56(Chemistry, Analytical)This paper reports a pioneering attempt at simultaneously analyzing gadolinium distribution and surface imaging of surrogate debris samples with homogeneous and heterogeneous composition using a fiber-coupled acoustic wave-assisted microchip laser-induced breakdown spectroscopy system. In this system, a microchip LIBS was used to measure the Gd distribution maps in the mixed oxide samples. Whereas, during elemental mapping by microchip LIBS, the laser-plasma acoustic waves were simultaneously recorded by microphone and applied for surface imaging of the samples. Additionally, the laser-plasma acoustic waves can be used to adjust the best-focusing position of the microchip LIBS because the acoustic wave amplitude is the strongest at the near best-focusing position. According to the measurement results, the emission spectra of the surrogate debris showed that the optical emission lines at 501.5 nm and 510.3 nm were suitable for Gd detection in the fuel debris sample. For Gd quantification, calibration curves were established from the intensity ratio of Gd and Ce emission lines. The surface imaging for the surrogate debris samples was successfully performed by collecting the laser-plasma acoustic waveforms during LIBS elemental mapping.
Batsaikhan, M.; 大場 弘則
not registered
特願 2023-119201 
公開特許公報
【課題】レーザ光を用いて対象物に含有する元素を分析する際に、対象物の表面の破壊を抑制し、高精度な元素分析を可能とする。 【解決手段】対象物(M)に対してレーザ光(22)を照射するレーザ照射部(40)を備えたレーザ装置(30)において、レーザ光(22)の照射により対象物(M)から生じる音波(24)を取得する音波取得部(50)を備え、レーザ照射部(40)は、音波取得部(50)にて取得された音波に基づいて所定の焦点位置に制御される、ことを特徴とする。
大場 弘則; Batsaikhan, M.; 赤岡 克昭; 狩野 貴宏; 岩田 圭弘; 若井田 育夫; 坂口 知聡*; 坂本 寛*; 牟田 浩明*
no journal, ,
福島第一原子力発電所(1F)炉内物質の分析手法として、ハイパースペクトルイメージング(HSI)とレーザー誘起ブレークダウン分光(LIBS)を組み合わせることを提案し、それぞれの分担において技術の適用性を検証している。東京電力福島第一原子力発電所の廃炉措置における燃料デブリ取出しに向けた位置・性状把握のための手段の一つとして、ファイバーLIBSによる遠隔その場分析が期待されている。しかしながら、LIBS技術において、対象物試料の元素分析を正しく行うためには、試料に対してパルスレーザー光を複数回照射して、プラズマ発光したときの信号強度を確認しながらレーザー光の焦点位置を調整する必要がある。そのため、焦点位置の調整の度に試料の表面が破壊されることや、本測定に至るまでの時間を要することなどが懸念される。今回、レーザー誘起音響波を利用してLIBS焦点位置の最適化を行い、同時に試料の2次元元素分布測定を試みた。その結果、音響波振幅の大きさと発光信号強度が一致し、分析に最適なレーザー光焦点位置を容易に決定することが可能となった。また、この方法を基礎にして多元素混合酸化物の組成分布が測定できることを実証した。
Batsaikhan, M.; 大場 弘則; 狩野 貴宏; 赤岡 克昭; 若井田 育夫
no journal, ,
In this invited talk, a brief discussion about fiber-coupled acoustic-wave assisted microchip LIBS (AW-mLIBS) system for elemental composition and surface imaging will be given.
Batsaikhan, M.; 大場 弘則; 若井田 育夫
no journal, ,
Laser Induced Breakdown Spectroscopy (LIBS) technique has been considered a promising analytical technique for the elemental composition of fuel debris (including Gd-thermal neutron absorber in some fuel rods) formed inside reactor vessels at FDNPP. However, accurate controlling of the laser focusing position is important to create plasma on the sample surface and to achieve the best analytical performance when the LIBS technique is applied to the in-situ and on-site investigation of nuclear fuel debris at FDNPP where various targets having different sizes and shapes must be recognized and analyzed in a short time under high radiation environment. The objective of the present study is to develop a method for the simultaneous measurement of elemental distribution and surface imaging of nuclear fuel debris using acoustic wave-assisted microchip LIBS system.
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.
Batsaikhan, M.; 大場 弘則; 狩野 貴宏; 赤岡 克昭; 若井田 育夫
no journal, ,
An acoustic-wave assisted microchip LIBS (AW-mLIBS) system was developed for simultaneous measurement of elemental mapping and surface recognition of fuel debris at the Fukushima Daiichi Nuclear Power Plant. In this presentation, an experimental study on the two-dimensional elemental mapping of Gadolinium (Gd) in a surrogate debris sample and surface imaging of the sample by the AW-mLIBS system will be presented.
Batsaikhan, M.; 狩野 貴宏; 柴田 卓弥; 赤岡 克昭; 若井田 育夫
no journal, ,
Severe accident at Fukushima Daiichi Nuclear Power Station (1F) of Tokyo Electric Power Company Holdings (TEPCO) occurred after strong earthquake and massive tsunami. Since after the accident, many efforts to decommissioning of the 1F moving forward steadily and safely. It is important to realize a measurement technique that can distinguish fuel debris from other materials. In the present study, we focused on Laser Induced Breakdown Spectroscopy (LIBS) which is considered as a promising remote, in-situ and radiation tolerance technique for fuel debris inspection of the 1F. Although the LIBS is a point measurement technique, it has been used as elemental surface mapping technique in many fields, because it allows user to realize fast spatial scanning without any sample preparation. In this presentation, measurement result of 2D elemental mapping by LIBS on simulated fuel debris sample under atmospheric pressure and without radiation environment will be discussed.
Batsaikhan, M.; 大場 弘則
no journal, ,
Laser-induced breakdown spectroscopy allows us to perform remote and rapid measurements with little or no sample preparation. And also, there have been continuous efforts to apply LIBS to nuclear material analysis. In the current situation, the inside of the Fukushima Daiichi Nuclear Power Station is filled with nitrogen gas. This time, we report and discuss the results of the fundamental plasma characteristics of Cu, Fe, and Zr elements in ambient gas. Plasma emission formed at the Fe, Cu, and Zr metals in the air at atmospheric pressure was collected as a function of lens-to-sample distance. As an example, the resulting spectra of Fe, the strongest intensity from Fe, O, and N was observed at lens-to-sample distance = 0 and all measurements in the present work were performed at this position. We will discuss the plasma temperature of each element and gas.
