Resonance lines are extensively used to diagnose electronic temperature Te and ions distribution. However, the analysis of the x-ray spectroscopy emitted from plasmas produced by a ns laser Jsually needs the help of a...Resonance lines are extensively used to diagnose electronic temperature Te and ions distribution. However, the analysis of the x-ray spectroscopy emitted from plasmas produced by a ns laser Jsually needs the help of a code or some assumptions. In this paper, a diagnostic idea of using line-pairs emitted from a doubly-excited state is proposed. By using the method presented in this paper, Te and the fractional population ratio of bare nuclei and H-like ions are directly obtained from the emission intensity ratios.展开更多
Laser-induced steel plasma is generated by focusing a Q-switched Nd:YAG visible laser(532 nm wavelength) with an irradiance of 1 x 109 W/cm2 on a steel sample in air at atmospheric pressure.An Echelle spectrograph ...Laser-induced steel plasma is generated by focusing a Q-switched Nd:YAG visible laser(532 nm wavelength) with an irradiance of 1 x 109 W/cm2 on a steel sample in air at atmospheric pressure.An Echelle spectrograph coupled with a gateable intensified charge-coupled detector is used to record the plasma emissions.Using time-resolved spectroscopic measurements of the plasma emissions,the temperature and electron number density of the steel plasma are determined for many times of the detector delay.The validity of the assumption by the spectroscopic methods that the laser-induced plasma(LIP) is optically thin and is also in local thermodynamic equilibrium(LTE) has been evaluated for many delay times.From the temporal evolution of the intensity ratio of two Fe I lines and matching it with its theoretical value,the delay times where the plasma is optically thin and is also in LTE are found to be 800 ns,900 ns and 1000 ns.展开更多
Spectroscopic emission of lead plasma, generated by the fundamental (1064 nm) and second harmonics (532 nm) of a Q-switched pulsed Nd: YAG laser, is studied. The spectral lines of neutral atoms and singly ionized...Spectroscopic emission of lead plasma, generated by the fundamental (1064 nm) and second harmonics (532 nm) of a Q-switched pulsed Nd: YAG laser, is studied. The spectral lines of neutral atoms and singly ionized lead ions were shown predominantly. The profiles of neutral lead lines observed were used to extract the excitation temperature using Boltzmann plots, whereas electron number density was determined from the profile of Stark broadened line. The variations of excitation temperature and electron number density as a function of laser energy were studied.展开更多
In this work,we studied the effects of the discharge current,gas flow rate and vessel pressure on the electron temperature and density of Ar plasma by Langmuir probe measurement.The argon plasma was created by a one-c...In this work,we studied the effects of the discharge current,gas flow rate and vessel pressure on the electron temperature and density of Ar plasma by Langmuir probe measurement.The argon plasma was created by a one-cathode arc source.The experimental results show that with increasing discharge current and gas flow rate,the electron temperature and density increase.It is found that when the discharge current is 70 A,90 A and HO A at an argon flow rate of2000 seem,the electron densities at about 0.186 m distance from the nozzle are 13.00×10^18 m^-3,14.04×10^18 m^-3 and 15.62×10^18 m^-3,and the electron temperatures are 0.38 eV,0.58 eV and0.71 eV,respectively.The positive I-V characteristic is explained.展开更多
Based on the theory of plasma continuous radiation, the relationship between the emission intensity of bremsstrahlung and recombination radiation and the plasma electron temperature is obtained. During the development...Based on the theory of plasma continuous radiation, the relationship between the emission intensity of bremsstrahlung and recombination radiation and the plasma electron temperature is obtained. During the development process of a return stroke of ground flash, the intensity of continuous radiation spectrum is separated on the basis of the spectrums with obviously different luminous intensity at two moments. The electron temperature of the lightning discharge channel is obtained through the curve fitting of the continuous spectrum intensity. It is found that electron temperature increases with the increase of wavelength and begins to reduce after the peak. The peak temperature of the two spectra is close to 25 000 K. To be compared with the result of discrete spectrum, the electron temperature is fitted by the O I line and N II line of the spectrum respectively. The comparison shows that the high temperature value is in good agreement with the temperature of the lightning core current channel obtained from the ion line information, and the low temperature at the high band closes to the calculation result of the atomic line, at a low band is lower than the calculation of the atomic line, which reflects the temperature of the luminous channel of the outer corona.展开更多
This study investigated the inductively coupled plasma etching reactor and RF coils developed by North Microelectronic Corporation. Full three dimensional simulations were made at different discharge conditions. The s...This study investigated the inductively coupled plasma etching reactor and RF coils developed by North Microelectronic Corporation. Full three dimensional simulations were made at different discharge conditions. The simulations examined and compared the distribution and non-uniformity of several plasma parameters at a fixed position upon the wafer at different pressures and coil currents. These parameters included electron density, electron temperature and power deposition. The results demonstrate that the electron density, power deposition and uniformity increase with either higher pressure or stronger coil currents, while the electron temperature decreases at this condition. Coil number increase can reduce the non-uniformity of parameters in the spatial distribution. The linear relationship between power deposition and electron density does not always exist. The comparison between simulation results and experiment results is also presented in the paper.展开更多
文摘Resonance lines are extensively used to diagnose electronic temperature Te and ions distribution. However, the analysis of the x-ray spectroscopy emitted from plasmas produced by a ns laser Jsually needs the help of a code or some assumptions. In this paper, a diagnostic idea of using line-pairs emitted from a doubly-excited state is proposed. By using the method presented in this paper, Te and the fractional population ratio of bare nuclei and H-like ions are directly obtained from the emission intensity ratios.
文摘Laser-induced steel plasma is generated by focusing a Q-switched Nd:YAG visible laser(532 nm wavelength) with an irradiance of 1 x 109 W/cm2 on a steel sample in air at atmospheric pressure.An Echelle spectrograph coupled with a gateable intensified charge-coupled detector is used to record the plasma emissions.Using time-resolved spectroscopic measurements of the plasma emissions,the temperature and electron number density of the steel plasma are determined for many times of the detector delay.The validity of the assumption by the spectroscopic methods that the laser-induced plasma(LIP) is optically thin and is also in local thermodynamic equilibrium(LTE) has been evaluated for many delay times.From the temporal evolution of the intensity ratio of two Fe I lines and matching it with its theoretical value,the delay times where the plasma is optically thin and is also in LTE are found to be 800 ns,900 ns and 1000 ns.
基金financially supported by the Higher Education Commission (HEC) and Pakistan Science Foundation (PSF-134)MCS, National University of Sciences & Technology (NUST) for encouragement in terms of provision of time and financial support to carry out research work
文摘Spectroscopic emission of lead plasma, generated by the fundamental (1064 nm) and second harmonics (532 nm) of a Q-switched pulsed Nd: YAG laser, is studied. The spectral lines of neutral atoms and singly ionized lead ions were shown predominantly. The profiles of neutral lead lines observed were used to extract the excitation temperature using Boltzmann plots, whereas electron number density was determined from the profile of Stark broadened line. The variations of excitation temperature and electron number density as a function of laser energy were studied.
基金supported by the International Thermonuclear Experimental Reactor(ITER) Program Special of Ministry of Science and Technology(No.2013GB114003)National Natural Science Foundation of China(Nos.11102221,11275135,11475122)
文摘In this work,we studied the effects of the discharge current,gas flow rate and vessel pressure on the electron temperature and density of Ar plasma by Langmuir probe measurement.The argon plasma was created by a one-cathode arc source.The experimental results show that with increasing discharge current and gas flow rate,the electron temperature and density increase.It is found that when the discharge current is 70 A,90 A and HO A at an argon flow rate of2000 seem,the electron densities at about 0.186 m distance from the nozzle are 13.00×10^18 m^-3,14.04×10^18 m^-3 and 15.62×10^18 m^-3,and the electron temperatures are 0.38 eV,0.58 eV and0.71 eV,respectively.The positive I-V characteristic is explained.
基金supported by National Natural Science Foundation of China(Grant No.11647150)Young Talents Program of Gansu Province of China(2016)Scientific Research Program of the Higher Education Institutions of Gansu Province of China(Grant No.2016A-068)
文摘Based on the theory of plasma continuous radiation, the relationship between the emission intensity of bremsstrahlung and recombination radiation and the plasma electron temperature is obtained. During the development process of a return stroke of ground flash, the intensity of continuous radiation spectrum is separated on the basis of the spectrums with obviously different luminous intensity at two moments. The electron temperature of the lightning discharge channel is obtained through the curve fitting of the continuous spectrum intensity. It is found that electron temperature increases with the increase of wavelength and begins to reduce after the peak. The peak temperature of the two spectra is close to 25 000 K. To be compared with the result of discrete spectrum, the electron temperature is fitted by the O I line and N II line of the spectrum respectively. The comparison shows that the high temperature value is in good agreement with the temperature of the lightning core current channel obtained from the ion line information, and the low temperature at the high band closes to the calculation result of the atomic line, at a low band is lower than the calculation of the atomic line, which reflects the temperature of the luminous channel of the outer corona.
基金supported by North Microelectronic Corporation (NMC).
文摘This study investigated the inductively coupled plasma etching reactor and RF coils developed by North Microelectronic Corporation. Full three dimensional simulations were made at different discharge conditions. The simulations examined and compared the distribution and non-uniformity of several plasma parameters at a fixed position upon the wafer at different pressures and coil currents. These parameters included electron density, electron temperature and power deposition. The results demonstrate that the electron density, power deposition and uniformity increase with either higher pressure or stronger coil currents, while the electron temperature decreases at this condition. Coil number increase can reduce the non-uniformity of parameters in the spatial distribution. The linear relationship between power deposition and electron density does not always exist. The comparison between simulation results and experiment results is also presented in the paper.