激光作用金属诱导等离子体行为分析.doc
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激光作用金属诱导等离子体行为分析,15800字34页摘要 激光诱导等离子体光谱分析（lips）技术是一种新型的技术的用来分析物质的元素构成。与传统的分析方法相比较，激光等离子体光谱分析方法具有操作简单，元素分析所需时间短，分析用到的样品量非常小，对样品几乎无损伤等优点，结合光纤技术还可以实现远距离操作。激光诱导等离子体光...
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激光作用金属诱导等离子体行为分析
15800字 34页
摘要 激光诱导等离子体光谱分析（LIPS）技术是一种新型的技术的用来分析物质的元素构成。与传统的分析方法相比较，激光等离子体光谱分析方法具有操作简单，元素分析所需时间短，分析用到的样品量非常小，对样品几乎无损伤等优点，结合光纤技术还可以实现远距离操作。激光诱导等离子体光谱技术已经被广泛的运用到冶金工业、环境监测、宇宙探索和医学制药等领域。
本文回顾了近几年各国学者在这项技术方面的研究取得的成果，介绍了等离子体的概念，激光诱导等离子体产生原理和实验分析需满足的两个前提条件。本实验将Nd:YAG激光器产生的激光聚焦到铁样品表面，延迟时间设为700ns，用Mechelle光谱仪记录了等离子体产生的辐射。着重研究了不同激光脉冲能量下（分别为3J、4J、5J、6J、7J）的等离子体谱线图。利用Boltzmann绘图法，拟合计算得到的各个点，获得拟合直线斜率，由此计算出等离子体中的电子温度；使用Stark展宽法，通过洛伦兹函数拟合对实验得到的谱线进行处理，获取特征谱线半高全宽由此计算得到等离子体的电子数密度。对等离子体的电子数密度和温度与激光的脉冲能量改变的变化趋势进行分析，可以看出随着激光能量逐渐增加，电子温度和电子数密度总体上是逐渐增加的，但是在等离子体屏蔽效应的影响下，不同脉冲能量下的等离子体电子温度和密度的增长趋势呈现出先快后慢再快的规律。
关键词：激光诱导等离子体 电子温度 电子数密度 激光脉冲能量
Behavior Analysis of Laser-Induced Metal Plasmas
Abstract Laser-induced plasma spectroscopy (LIPS) is a new technology of material element analysis. This technique has lots of advantages when we compare it with the traditional analysis method. For example, its operation is simple, we can quickly get the result of analysis and there is almost no damage to the sample. We can realize remote-controlled operation if we take the help of fiber. The laser-induced plasma spectroscopy has been widely applied to metallurgical industry, environment monitoring, space exploration and medicine pharmacy, etc.
The present paper reviews the achievements of LIPS which are achieved by the international scholars in recent years. This paper also introduces the concept and generation principle of laser-induced plasma. We should meet two conditions in this experiment. We focus the Nd: YAG laser (wavelength 1064 nm) on iron samples, we use an Echelle spectrograph to record the plasma emissions. The delay time we set is 700 ns. We mainly study the plasma spectrum under different laser pulsed energy (3J, 4J, 5J, 6 J, 7J) in this paper. The value of temperature T can be determined from the slope of Boltzmann plot；We use the Stark broadening method for determining the electron number density ne, which need using Lorentz fitting for calculating the half-width of the plasma emission. When we analyze the plasma electron temperature and electron number density, we get their change trend along with the laser pulse energy, from which we can find that when laser energy is increasing, the plasma electron temperature and density is gradually increasing on the whole. However, due to the effect of plasma shielding, the plasma electron temperature and density under different pulse energy has different growth trend, which is fast at beginning, then becomes slowly and fast at the end.
Keywords laser-induced plasma electron temperature electron number density laser pulse energy
目录
摘要 1
第一章 绪论 1
1.1课题研究背景和研究意义 1
1.2激光等离子体光谱技术的发展和研究现状 2
1.2.1激光诱导等离子体的发展历史 2
1.2.2国内外的研究成果 2
1.3 本文研究内容 7
第二章 激光诱导等离子体的基本原理 9
2.1等离子体含义 9
2.2等离子体产生机理 9
2.3研究等离子体性质应满足的两个假设条件 10
2.4激光诱导等离子体的电子体温度计算 10
2.5等离子体电子数密度计算 12
第三章 实验装置及结果分析 14
3.1实验装置原理图 14
3.2实验结果与分析 15
3.2.1不同能量密度下谱线相对强度的变化 17
3.2.2不同能量密度下等离子体温度的变化分析 18
3.2.3等离子体电子数密度随激光脉冲能量的变化分析 21
3.2.4局部热运动平衡分析 24
第四章 总结与展望 26
致谢 28
参考文献 29
15800字 34页
摘要 激光诱导等离子体光谱分析（LIPS）技术是一种新型的技术的用来分析物质的元素构成。与传统的分析方法相比较，激光等离子体光谱分析方法具有操作简单，元素分析所需时间短，分析用到的样品量非常小，对样品几乎无损伤等优点，结合光纤技术还可以实现远距离操作。激光诱导等离子体光谱技术已经被广泛的运用到冶金工业、环境监测、宇宙探索和医学制药等领域。
本文回顾了近几年各国学者在这项技术方面的研究取得的成果，介绍了等离子体的概念，激光诱导等离子体产生原理和实验分析需满足的两个前提条件。本实验将Nd:YAG激光器产生的激光聚焦到铁样品表面，延迟时间设为700ns，用Mechelle光谱仪记录了等离子体产生的辐射。着重研究了不同激光脉冲能量下（分别为3J、4J、5J、6J、7J）的等离子体谱线图。利用Boltzmann绘图法，拟合计算得到的各个点，获得拟合直线斜率，由此计算出等离子体中的电子温度；使用Stark展宽法，通过洛伦兹函数拟合对实验得到的谱线进行处理，获取特征谱线半高全宽由此计算得到等离子体的电子数密度。对等离子体的电子数密度和温度与激光的脉冲能量改变的变化趋势进行分析，可以看出随着激光能量逐渐增加，电子温度和电子数密度总体上是逐渐增加的，但是在等离子体屏蔽效应的影响下，不同脉冲能量下的等离子体电子温度和密度的增长趋势呈现出先快后慢再快的规律。
关键词：激光诱导等离子体 电子温度 电子数密度 激光脉冲能量
Behavior Analysis of Laser-Induced Metal Plasmas
Abstract Laser-induced plasma spectroscopy (LIPS) is a new technology of material element analysis. This technique has lots of advantages when we compare it with the traditional analysis method. For example, its operation is simple, we can quickly get the result of analysis and there is almost no damage to the sample. We can realize remote-controlled operation if we take the help of fiber. The laser-induced plasma spectroscopy has been widely applied to metallurgical industry, environment monitoring, space exploration and medicine pharmacy, etc.
The present paper reviews the achievements of LIPS which are achieved by the international scholars in recent years. This paper also introduces the concept and generation principle of laser-induced plasma. We should meet two conditions in this experiment. We focus the Nd: YAG laser (wavelength 1064 nm) on iron samples, we use an Echelle spectrograph to record the plasma emissions. The delay time we set is 700 ns. We mainly study the plasma spectrum under different laser pulsed energy (3J, 4J, 5J, 6 J, 7J) in this paper. The value of temperature T can be determined from the slope of Boltzmann plot；We use the Stark broadening method for determining the electron number density ne, which need using Lorentz fitting for calculating the half-width of the plasma emission. When we analyze the plasma electron temperature and electron number density, we get their change trend along with the laser pulse energy, from which we can find that when laser energy is increasing, the plasma electron temperature and density is gradually increasing on the whole. However, due to the effect of plasma shielding, the plasma electron temperature and density under different pulse energy has different growth trend, which is fast at beginning, then becomes slowly and fast at the end.
Keywords laser-induced plasma electron temperature electron number density laser pulse energy
目录
摘要 1
第一章 绪论 1
1.1课题研究背景和研究意义 1
1.2激光等离子体光谱技术的发展和研究现状 2
1.2.1激光诱导等离子体的发展历史 2
1.2.2国内外的研究成果 2
1.3 本文研究内容 7
第二章 激光诱导等离子体的基本原理 9
2.1等离子体含义 9
2.2等离子体产生机理 9
2.3研究等离子体性质应满足的两个假设条件 10
2.4激光诱导等离子体的电子体温度计算 10
2.5等离子体电子数密度计算 12
第三章 实验装置及结果分析 14
3.1实验装置原理图 14
3.2实验结果与分析 15
3.2.1不同能量密度下谱线相对强度的变化 17
3.2.2不同能量密度下等离子体温度的变化分析 18
3.2.3等离子体电子数密度随激光脉冲能量的变化分析 21
3.2.4局部热运动平衡分析 24
第四章 总结与展望 26
致谢 28
参考文献 29
