激光烧蚀脉冲放电激发的土壤等离子体电子数密度和温度的研究

以激光烧蚀快脉冲放电激发土壤为例,研究了激光烧蚀快脉冲放电等离子体技术产生的土壤等离子体的电子数密度和温度。根据实验测得的Si原子和离子谱线的强度和萨哈玻尔兹曼方程,计算了等离子体的电子温度,并从分析Si I 250.69nm谱线的斯塔克展宽中导出了等离子体的电子数密度。与使用同样激光能量激发的激光等离子体相比,激光烧蚀快脉冲放电激发等离子体的电子数密度和温度都明显增加,与观察到的光谱信号强度是一致的。     

Comparative Study on Excitation Temperature,Electron Temperature and Electron Density in an Atmospheric Argon Microwave Plasma

An infinite-volume of atmospheric argon microwave plasma is produced in the microwave plasma source based on the inductive coupling window-rectangular resonator under the input of the microwave power at 2.45 GHz. The excitation temperature of the plasma is studied by using the Boltzmann plot of Ar I lines in two different wavelength ranges while the electron temperature is researched by using line-to-continuum intensity ratio of Ar I lines. The electron density is compared by using the Stark broadenings of At I lines at 522.13nm and 549.59nm and Ha line at 486.13nm.     

Spectroscopic Measurement of Electron Temperature and Density in an Argon Plasma Jet Based on Collisional‐Radiative Model

The present paper describes a spectroscopic method or determining electron temperature T_e and density N_e in an argon plasma jet on the basis of a Collisional‐Radiative model of argon. Electron temperature and density in the argon plasma were measured by the method developed, and comparison of them was discussed with those obtained with a Langmuir probe. The results or T_e and N_e obtained by the spectroscopic method agreed roughly with those by the probe.     

等离子体电子温度的发射光谱法诊断

电子温度是表征等离子体性质的一个重要参数。由于等离子体放电过程非常复杂,要实时准确测定其电子温度值非常困难。发射光谱法作为一种等离子体诊断技术,因其所使用的仪器相对简单,并采用非接触测量,灵敏度高,响应速度快,可广泛地应用于各种等离子体性质的研究和参数的诊断。文章介绍了测定等离子体电子温度的双谱线法、多谱线斜率法、等电子谱线法、Saha-Boltzmann法、谱线绝对强度法等多种发射光谱法,同时综述了这些方法在等离子体电子温度诊断中的应用,旨在为实际过程中选择合适的等离子体诊断方法提供参考。     

光学发射光谱法测量氩气微空心阴极放电中特性参数

针对微空心阴极放电(MHCD)装置,通过在氩气中添加少量氮气,分析氮分子第一正带系N2(B3ΠgA3u+)发射光谱的方法测量了MHCD中的气体温度,通过氩气中混有的少量氢气,分析Hβ谱线Stark加宽得到电子数密度。研究表明,MHCD在极小的体积和很高的功率密度下维持放电,致使发生了明显的气体加热现象,气体温度可高于700 K,并且随着放电室压强和放电电流呈有规律的变化,具有较好的可控性,电子数密度的量级为1014～1015cm-3。通过对不同条件下等离子体特性参数的诊断和分析,得到了其量级和变化规律,对MHCD的广泛研究和应用提供了重要的实验数据和技术支持。     

大气压氩气介质阻挡放电中的电子激发温度

采用发射光谱强度比法,测量了大气压氩气介质阻挡放电(DBD)中的电子激发温度。实验在690～800 nm的范围内测量了大气压氩气DBD的发射光谱,经分析发现这些谱线全部是氩原子的发射谱线。为了测量电子激发温度,选用相距较近的763.51 nm(2P₆→1S₅),772.42 nm(2P₂→1S₃)的两条光谱线。结果发现电子温度的范围为0.1～0.5 eV,电子激发温度随电压的增加而增加,随流量的增加而减小。实验还发现氩气流动与非流动时电子激发温度有明显的差别。上述结果对介质阻挡放电在工业领域上的应用具有重要意义。     

大气压氩气放电六边形斑图的电子激发温度研究

采用特殊设计的气体介质阻挡放电实验装置,对大气压氩气放电六边形斑图的放电信号及激发光谱进行了测量。采用发射光谱强度比法,计算了放电丝呈六边形斑图时的电子激发温度。实验发现,随着驱动电压频率的升高,六边形斑图的电子激发温度明显升高,各放电通道之间的放电时间相关程度提高。该工作对控制斑图的形成和研究斑图动力学具有重要参考价值。     

Determination of the Electron Density in an Argon Laser Plasma by Spectroscopy of the Hydrogen Hα and Hβ Lines

From measurements of the H_α and H_β spectral line profiles in a plasma, a method is developed which allows to separate the contributions of Doppler and Stark broadening. This method is superior to the deconvolution of Voigt profiles, in particular, when the lines are of low intensity. The electron density in the plasma can be calculated from the Stark broadening. An example is the low pressure (p ≈ 1 hPa) arc discharge of argon ion lasers which is characteristised by electron densities of approximately 10¹⁴ cm^?3 at heavy particle temperatures of about 10⁴ K. These plasma parameters lead to a broadening of the Balmer H_α and H_β spectral lines of hydrogen, which has a low concentration within the discharge area. The spectral lines are broadened due to the electron density dependent Stark effect and the temperature responsive Doppler effect. The results are consistent with predictions of the argon ion laser modelling.     

Optical Emission Spectroscopy Used to Study the Characteristics of the Capacitive Radio-Frequency Discharge in Argon

Capacitively coupled radio-frequency (13.56 MHz) glow discharge in argon at low pressure (200 mTorr) has been studied by optical emission spectroscopy (OES) and electrical probe. Increasing power density resulted in lowering of the electron temperature T _e and increase of the electron density n _e. The to transition in this case takes place smoothly. The intensity (I _750.4) of the emission line at 750.4 nm due to 2p₁1s₂ transition closely follows the variation of n _e with power density. Calculation of the electron-energy probability function shows that electron occupation mainly changes in the high-energy tail, which explains close resemblance of I _750.4 to n _e. At moderate pressures, only OES method was applied to observe - transition which is abrupt in this pressure range.     

弓网电弧温度及导电特性的光谱分析

高铁提速受多方面因素制约，其中弓网离线对受流质量影响很大。在滑动接触模式下，受电弓与接触网的磨损均很严重。弓网离线产生的电弧是造成接触网和受电弓磨损的主要原因之一。电弧温度高，还具有电离特性，因此一般的传感器无法置于电弧中测量。光谱分析法在研究弓网电弧的温度及电子密度方面具有明显优势，基于此可进一步寻找耐磨损的新材料或者灭弧方法。因接触网使用铜合金材料，故选取铜元素特定光谱作为研究对象。采用Boltzman作图法，通过实验测得弓网电弧的光谱信息，进而计算电弧通道的温度。结果表明，由于单次电弧持续时间短又受弓网相对运动的影响，其温度并不很高，且电弧温度随着电弧持续时间的增加而增加。采用盲目反卷积的方法求解307.92 nm谱线的Stark展宽，再根据Stark展宽求得电弧的电子密度，结果表明弓网电弧通道的电子密度和其他种类电弧电子密度在同一数量级上；说明电弧引起的粒子电离效应明显。由此可知光谱法在电弧温度及电弧电离特性的分析中是较为方便和准确的。     

COmparison of Some Basic Plasma Parameters and Discharge Characteristics of Planar Magnetron Sputtering Discharges in Argon and Neon

A comparative investigation is carried out of the discharge characteristics (current-voltage characteristic and dependence of the running voltage on the gas pressure at constant discharge current), as well as of some plasma parameters (electron temperature, floating potential and plasma potential) and densities of the ion current extracted to the substrate, for discharges in neon and argon in a planar magnetron system for sputtering with a graphite target.     

光谱法诊断大气压等离子体电子密度

采用发射光谱方法对大气压氩气介质阻挡放电(DBD)系统中的电子密度进行了诊断。通过考虑放电等离子体中的各种加宽机制, 采用自编的非对称卷积程序对氩原子发射谱线的线型进行分析拟合, 再通过反卷积的方法将各种加宽机制分离开来, 最终将Stark展宽分离出来进行大气压氩气介质阻挡放电电子密度的计算。诊断结果表明, 在大气压氩气介质阻挡放电中当有三个放电丝存在, 电子温度为10000 K时, 电子密度约为4.06×1021 m-3, 诊断结果和模拟结果符合得很好。此方法不仅可以应用在大气压介质阻挡放电中, 还可以用于其他含有非氢气体的大气压等离子体电子密度的测量。     

压强对空气/氩气介质阻挡放电中等离子体温度的影响

使用水电极介质阻挡放电装置,在氩气和空气的混合气体放电中,利用发射光谱法,研究了电子激发温度和分子振动温度随气体压强的变化关系。通过氩原子763.51 nm(2P₆→1S₅)和772.42 nm(2P₆→1S₃)两条谱线强度比法计算电子激发温度;通过氮分子第二正带系(C3Π_u→B3Π_g)的发射谱线计算氮分子的振动温度;对氮分子离子391.4 nm和激发态的氮分子337.1 nm两条发射谱线的相对强度进行了测量,以进一步研究电子能量的变化。实验表明,随着压强从20 kPa增大到60 kPa, 电子激发温度减小,分子振动温度减小, 氮分子离子谱线与激发态的氮分子谱线强度之比减小。     

Pressure Dependence of the Mean Electron Energy in the Bulk Plasma of an RF Discharge in Argon

The pressure dependence of the mean electron energy 〈?〉 was investigated in discharges in Ar experimentally by sampling the plasma potential with an ion mass spectrometer, and theoretically by solving the electron Boltzmann equation for the bulk plasma. Both results show a decrease in 〈?〉 with increasing pressure in the regime between 0.2 and 40 Pa although this behaviour is much more pronounced in the experimental results. The results are compared to those of single-probe measurements of other authors. In one case they are in good agreement [10], while there is a discrepancy in another case [11]. Possible reasons for this behaviour are discussed. The advantage of the mass spectrometric sampling method is, that it is absolutely non-invasive, so that also in sensitive processes no contamination will occur.     

Temperature Determination from the Continuous Emission of a Dense Argon Plasma

The temperature of the laser sustained plasma has been determined from the continuum emission coefficient at different wavelengths. The experiments were performed in an argon plasma at the pressure of 10 atm. The spurious continuum resulting from merging of spectral lines was investigated numerically. Its influence on the measured emission coefficient in the red region has been found to be considerable.     

Determination of Spatial Distributions of Plasma Parameters of a Compact Magnetron Discharge

Physics of Atomic Nuclei - In this paper, the hardware-software high resolution measuring system for studying the spatial and spectral distributions of the radiation intensity of a magnetron...     

氩气含量对介质阻挡放电中单丝等离子体温度的影响

在空气与氩气组成的混合气体放电中,首次研究了由中心点和外层晕组成的单丝。从照片中观察单丝结构,发现混合气体中氩气所占的比例越重,单丝的直径随之越小,同时中心点和外层晕的亮度有明显的差异,说明中心点和外层晕可能处于不同的等离子体状态。实验对单丝结构进行了光学时空分辨测量,研究了中心点和外层晕两层结构的微观特性。利用发射光谱法,详细地研究了该单丝结构的中心点和外层晕的等离子体参数随氩气含量的变化关系。实验根据氮分子第二正带系(C3Π_u→B3Π_g)谱线计算了中心点和外层晕的分子振动温度;通过氮分子离子N+₂(391.4 nm) 第一负带系谱线与氮分子N₂(394.1nm)谱线强度比,反映中心点和外层晕的电子平均能量随氩气含量的变化关系;利用氩原子763.2 nm(2P₆→1S₅)和772.077 nm(2P₂→1S₃)两条谱线的相对强度比法,估算了中心点和外层晕的电子激发温度。结果表明：中心点的光信号对应着第一个电流脉冲, 且其光信号较弱;而外层晕的光信号同时对应着第一个和第二个电流脉冲, 且其光信号较强。在相同的氩气含量条件下,外层晕比中心点的分子振动温度、电子平均能量以及电子激发温度均要高。随着氩气含量从30%逐渐增大到50%,中心点和外层晕的分子振动温度是逐渐减小的,而电子平均能量和电子激发温度均是逐渐增大的。     

A Calculation of the Electron Temperature of Complex Plasma of Noble Gases Mixture in CCRF Discharge

In this paper the results of studying of the electron temperature of buffer and complex plasmas in mixtures of noble gases (helium + argon) in capacitively coupled radiofrequency (CCRF) discharge are presented. The optical properties of dusty plasma in argon, helium and their mixtures have been studied using optical diagnostic methods. Based on spectral lines of plasma forming gases, the dependence of the electron temperature on gas pressure and discharge power has been determined. The axial distribution of electron temperature in the interelectrode gap has been measured. Measurements have been made using an RF compensated electric probe. The comparison of the experimental results shows that admixture of a small amount of argon to helium leads to a decrease in the electron temperature of buffer plasma. The presence of dust particles in the plasma causes an increase in the electron temperature. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A Linear Model for the Interpretation of Optical Emission Spectroscopy Measurements in Low Pressure DC Magnetron Sputtering

For a balanced dc magnetron discharge a linear model for the formation of excited and ionized species is presented. The consideration is based on collisional kinetic theory and a correlation of discharge current with ionization rates, and leads to normalized rate coefficients. The electron energy distribution changes according to the determining external parameters, but needs neither to be known in detail nor to be of Maxwellian type. The model calculations are consistent with measurements done by optical emission spectroscopy (OES) on the magnetron sputtering of aluminium in argon discharges. The dependences of optical emission intensities on discharge current and on argon pressure show that both, excited argon atoms as well as excited argon ions, are generated from neutral argon by direct, fast electron impact. It is additionally shown that at least for low argon pressure the excitation of aluminium atoms is also caused by direct electron impact.     

光谱诊断冷等离子体作用下甲烷转化机理的初步研究(英文)

冷等离子体是甲烷无氧活化制C2烃较为有效的技术手段之一,由于等离子体反应体系的复杂性,甲烷无氧活化制C2烃反应机理及过程尚不十分清楚。本文采用发射光谱原位诊断技术对冷等离子体作用下甲烷无氧活化制C2烃反应中若干激发态物种进行诊断研究,在250nm～670nm波长范围内检测到下列激发态物种:CH、C和C2。依据激发态物种检测结果、气相色谱反应产物分析结果及等离子体特性,推断了等离子体作用下甲烷无氧活化制C2烃的自由基反应历程。