Enhancement of LIBS emission using antenna-coupled microwave
マイクロ波のアンテナ入射によるLIBS発光量の増大効果
Khumaeni, A.; 反保 元伸; 赤岡 克昭 ; 宮部 昌文 ; 若井田 育夫
Khumaeni, A.; Tampo, Motonobu; Akaoka, Katsuaki; Miyabe, Masabumi; Wakaida, Ikuo
レーザー誘起発光分光法(LIBS)における発光信号の増大を図るため、ループアンテナ(直径3mm)を用いてマイクロ波を照射し、その効果を確かめた。減圧空気条件下で、酸化ガドリニウム試料にNd:YAGレーザー光(532nm, 10ns, 5mJ)を集光照射し、これに同期してパルスマイクロ波を入射した結果、温度が高い状態で長時間プラズマ発光が維持され、時間積分した発光信号量は、従来のマイクロ波を用いないLIBS信号に比較して32倍の発光信号量が得られた。酸化ガドリニウム試料に酸化カルシウムを微量混入させた試料を用いてカルシウム検出量に関する検量線を求めた結果、良好な直線性と2mg/kgの検出下限感度を得た。核燃料物質等のその場分析の高感度化に有用である。
Intensified microwave coupled by a loop antenna (diameter of 3 mm) has been employed to enhance the laser-induced breakdown spectroscopy (LIBS) emission. In this method, a laser plasma was induced on GdO sample at a reduced pressure by focusing a pulsed Nd:YAG laser (532 nm, 10 ns, 5 mJ) at a local point, at which electromagnetic field was produced by introducing microwave radiation using loop antenna. The plasma emission was significantly enhanced by absorbing the microwave radiation, resulting in high-temperature plasma and long-lifetime plasma emission. By using this method, the enhancement of Gd lines was up to 32 times, depending upon the emission lines observed. A linear calibration curve of Ca contained in the GdO sample was made. The detection limit of Ca was approximately 2 mg/kg. This present method is very useful for identification of trace elements in nuclear fuel and radioactive materials.