Hydrogen and Deuterium Analysis Using Laser-Induced Plasma Spectroscopy

激光诱导等离子体光谱（LIPS）作为一种快速定量分析工具，在许多领域得到了广泛的应用。然而，由于氢在固体材料中的杂质含量一般，分析工作很少报道。LIPS在1atm下进行，氢发射（Hα）发生严重的谱线展宽，发射效率急剧下降。在本研究中，我们已经证明，H分析可以实现通过控制一些条件，在激光等离子体的生产，如环境气体的压力，气体的种类和激光聚焦。作为氢分析的应用之一，我们对核电站工业中非常重要的问题--Zicaloy合金样品进行了氢分析。1）减压下的氢分析研究发现，在10 Torr左右的氦低压下，固体中的氢分析具有良好的条件。高灵敏度和高精度的分析表明，在zicaloy样品（含H在200 ppm和4300 ppm的范围内）通过采用相当极端的散焦条件（f= 200 m透镜为-45 mm），在140 mJ的YAG激光照射下，线性关系良好，检出限约为50 ppm。2）在1atm的He气体中，建立了一种新的激发技术;即通过He亚稳态（He*）激发。为此，YAG激光脉冲被有意地聚焦在样品表面上方10 mm处，以便诱导气体击穿等离子体，其中产生He* 原子，以及从样品表面的激光烧蚀。3）氘分析我们还证明了通过抑制Hα和Dα的光谱展宽，可以同时进行H和D（氘）的分析。然而，峰值波长偏移仅为0.18nm。

Laser-induced plasma spectroscopy (LIPS) has been expanded in many fields as a rapid quantitative analytical tool. However, little work has been reported on the analysis of hydrogen as impurity in solid materials because ordinary. LIPS is conducted at 1 atm, under which condition hydrogen emission (Hα) undergoes a severe line broadening and drastic diminishing in emission efficiency. In this study we have demonstrated that H analysis can be realized by controlling some conditions in the laser plasma production, such as ambient gas pressure, gas kind and laser focusing. As one of the application of H analysis, we have made H analysis in Zicaloy sample, which is very important issue in the nuclear power station industry.1) H analysis at reduced pressureIt has been found that helium low pressure around 10 Torr offers a good condition for H analysis in solids. High sensitive and high precision analysis was demonstrated on zicaloy samples (containing H in the range from 200ppm and 4300ppm) by employing rather extreme defocusing condition (-45mm for f=200m lens) for YAG laser irradiation(140mJ), presenting a good linear calibration curve with a detection limit of about 50ppm.2)H analysis in He gas at 1 atmAnother excitation technique was developed; namely, excitation through He metastable-state(He*). For this purpose, YAG laser pulse was intentionally focused at 10mm above the sample surface so as to induce a gas breakdown plasma, where He*atoms are produced, together with the laser ablation from the sample surface. It was confirmed that a good linear calibration curve is available even in this case with a detection limit of around 100ppm.3) Deuterium analysisWe have also proved that H and D(deuterium) analysis can be made simultaneously by suppressing the spectra broadening of Hα and Dα., nevertheless the peak wavelength shift is only 0.18nm..