Pub Date : 2008-06-15DOI: 10.1109/PLASMA.2008.4590954
D. Abe, J. Qiu, B. Levush, D. Pershing, E. Wright, K. Nguyen, F. Wood, R. Myers, E. Eisen, I. Chernyavskiy, A. Vlasov
We describe the results of recent experiments with an eight- beam, five-cavity multiple-beam klystron (MBK). The electron gun is of the same design as used in our previous MBK and operates at a nominal cathode voltage of -45 kV and a total current of 32 A. The electrodynamic circuit is comprised of a two-gap input cavity, a two-gap idler cavity, two additional single-gap idler cavities, and a two-gap output cavity and has a total length of 22 cm. All of the multi-gap cavities operate in the pi-mode. Some of the cavities were loaded with a lossy dielectric to reduce the Q. Output power is extracted from both of the output resonator gaps in four waveguide arms (two on each gap). The tube produces ~ 600 kW of peak output power at saturation with a corresponding electronic efficiency of 40%. Beam transmission is excellent: > 99% in the small-signal regime and > 93% at saturation. Despite a mismatch in the input circuit that reduces the gain in the upper portion of the band, the MBK has a measured 3-dB bandwidth of ~ 6%. We will describe efforts to improve the input circuit match and will compare measured data with the results of numerical modeling using the MAGIC 3D particle-in-cell code and the 2.5D large-signal code, TESLA.
{"title":"Experimental results from an 8-beam, 5-cavity multiple-beam klystron with 6% bandwidth","authors":"D. Abe, J. Qiu, B. Levush, D. Pershing, E. Wright, K. Nguyen, F. Wood, R. Myers, E. Eisen, I. Chernyavskiy, A. Vlasov","doi":"10.1109/PLASMA.2008.4590954","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4590954","url":null,"abstract":"We describe the results of recent experiments with an eight- beam, five-cavity multiple-beam klystron (MBK). The electron gun is of the same design as used in our previous MBK and operates at a nominal cathode voltage of -45 kV and a total current of 32 A. The electrodynamic circuit is comprised of a two-gap input cavity, a two-gap idler cavity, two additional single-gap idler cavities, and a two-gap output cavity and has a total length of 22 cm. All of the multi-gap cavities operate in the pi-mode. Some of the cavities were loaded with a lossy dielectric to reduce the Q. Output power is extracted from both of the output resonator gaps in four waveguide arms (two on each gap). The tube produces ~ 600 kW of peak output power at saturation with a corresponding electronic efficiency of 40%. Beam transmission is excellent: > 99% in the small-signal regime and > 93% at saturation. Despite a mismatch in the input circuit that reduces the gain in the upper portion of the band, the MBK has a measured 3-dB bandwidth of ~ 6%. We will describe efforts to improve the input circuit match and will compare measured data with the results of numerical modeling using the MAGIC 3D particle-in-cell code and the 2.5D large-signal code, TESLA.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"93 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83838714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-06-15DOI: 10.1109/PLASMA.2008.4591159
G. Herdrich, M. Auweter-Kurtz, D. Bock, M. Fertig, D. Haag, A. Nawaz, H. Roser
This paper presents recent developments in the field of electric propulsion for interplanetary missions such as the arcjet system TALOS and the magnetoplasmadynamic thrusters Van-Allen belt and SIMP-LEX. Investigations include measurement of mass bit, plasma current, plasma acceleration time, plasma thrust, and plasma dynamic properties. Thruster optimization includes ground testing, numerical simulations as well as thermal modelling.
{"title":"Development of electric propulsion systems at IRS","authors":"G. Herdrich, M. Auweter-Kurtz, D. Bock, M. Fertig, D. Haag, A. Nawaz, H. Roser","doi":"10.1109/PLASMA.2008.4591159","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4591159","url":null,"abstract":"This paper presents recent developments in the field of electric propulsion for interplanetary missions such as the arcjet system TALOS and the magnetoplasmadynamic thrusters Van-Allen belt and SIMP-LEX. Investigations include measurement of mass bit, plasma current, plasma acceleration time, plasma thrust, and plasma dynamic properties. Thruster optimization includes ground testing, numerical simulations as well as thermal modelling.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"63 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79196699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-06-15DOI: 10.1109/PLASMA.2008.4590797
T. Scherer, R. Heidinger, A. Meier, K. Takahashi, K. Kajiwara, K. Sakamoto
For the plasma engineering of ITER, EC launchers will be used at the mid and top port levels. The EU is preparing the procurement of the upper port plug and JA the procurement of the equatorial. Part of these studies is to verify the window design and to work out, whether a concept is available for both launchers. To this goal, first experiments with low and high power mm-waves are performed and will be presented. The high power RE behavior of torus window assemblies with corrugated waveguides is being investigated by using IR imaging technique during high power microwave loading up to 1 MW at a frequency of 170 GHz at the JAEA gyrotron facility. Short and long pulse experiments are being performed to determine the temperature distribution over the whole diamond window area and the efficiency of the indirect cooling by a copper cuff. The occurrence of arcing is being studied as part of evaluation of the assembly design. For a characterization of the dielectric losses a low power measurement in a Fabry-Perot resonator setup at 170 GHz of the bare as-grown diamond disk will be compared with the brazed disk in the window housing. The evaluation of the curvature of the diamond disk is used as indicator of the residual stresses introduced in the joining process.
{"title":"Microwave testing of a CVD diamond torus window prototype for iter","authors":"T. Scherer, R. Heidinger, A. Meier, K. Takahashi, K. Kajiwara, K. Sakamoto","doi":"10.1109/PLASMA.2008.4590797","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4590797","url":null,"abstract":"For the plasma engineering of ITER, EC launchers will be used at the mid and top port levels. The EU is preparing the procurement of the upper port plug and JA the procurement of the equatorial. Part of these studies is to verify the window design and to work out, whether a concept is available for both launchers. To this goal, first experiments with low and high power mm-waves are performed and will be presented. The high power RE behavior of torus window assemblies with corrugated waveguides is being investigated by using IR imaging technique during high power microwave loading up to 1 MW at a frequency of 170 GHz at the JAEA gyrotron facility. Short and long pulse experiments are being performed to determine the temperature distribution over the whole diamond window area and the efficiency of the indirect cooling by a copper cuff. The occurrence of arcing is being studied as part of evaluation of the assembly design. For a characterization of the dielectric losses a low power measurement in a Fabry-Perot resonator setup at 170 GHz of the bare as-grown diamond disk will be compared with the brazed disk in the window housing. The evaluation of the curvature of the diamond disk is used as indicator of the residual stresses introduced in the joining process.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"12 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83231607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-06-15DOI: 10.1109/PLASMA.2008.4590625
A. Ağıral, J. Gardeniers
Atmospheric pressure field emission operation of 2 mum gap diode utilizing crystalline W18O49 nanowires, which were grown on sputter deposited tungsten films by thermal annealing at 700degC in ethene and nitrogen, was demonstrated. Field emission measurements in air follows Fowler-Nordheim electron tunneling theory and showed a low turn-on field of 3.3 V/mum, excellent stability and reproducibility with high emission current density (28 mA/cm2). At high electric fields (> 13 V/mum), current density diverged from Fowler-Nordheim equation and space charge limited conduction was observed. Explosion of emitters was observed similar to breakdown of small contact gaps in vacuum under overloading with high density field emission current. Resistive heating and the Nottingham mechanism may have produced the increased temperature during emission. Viability of pulsed electron emission at atmospheric pressure was demonstrated by applying a 100 Hz square wave voltage to the cathode. Pulsed electron emission with good repetition rate was observed.
{"title":"Atmospheric pressure field electron emission from nanostructures","authors":"A. Ağıral, J. Gardeniers","doi":"10.1109/PLASMA.2008.4590625","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4590625","url":null,"abstract":"Atmospheric pressure field emission operation of 2 mum gap diode utilizing crystalline W18O49 nanowires, which were grown on sputter deposited tungsten films by thermal annealing at 700degC in ethene and nitrogen, was demonstrated. Field emission measurements in air follows Fowler-Nordheim electron tunneling theory and showed a low turn-on field of 3.3 V/mum, excellent stability and reproducibility with high emission current density (28 mA/cm2). At high electric fields (> 13 V/mum), current density diverged from Fowler-Nordheim equation and space charge limited conduction was observed. Explosion of emitters was observed similar to breakdown of small contact gaps in vacuum under overloading with high density field emission current. Resistive heating and the Nottingham mechanism may have produced the increased temperature during emission. Viability of pulsed electron emission at atmospheric pressure was demonstrated by applying a 100 Hz square wave voltage to the cathode. Pulsed electron emission with good repetition rate was observed.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"29 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81162522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-06-15DOI: 10.1109/PLASMA.2008.4591120
N. Denisova
Summary form only given. A review of applications of the tomographic method for diagnostics of various plasma objects has been performed in this work. The objects are: methane plasma evolution in plasma-chemical reactor, a capillary discharge of inner diameter of 1 mm, a high-pressure non-symmetrical arc plasma, a high frequency inductive coupled plasma. The computed tomography is receiving increasing attention as a powerful method for the reconstruction of the local characteristics in both: high-temperature and low-temperature plasma. Local plasma characteristics can be derived from the integrated data by combining of an integrating measurement techniques and computer tomography algorithms and methods. This can provide much useful information on the plasma structure and its evolution in time. There are various theoretical approaches on the development of algorithms for obtaining tomographic images, such as algebraic reconstruction technique, maximum entropy method, minimum Fisher information algorithm, constrained optimization and maximum a posteriori methods. These algorithms are intended to be applied in different class of reconstruction problems corresponding to different kinds of prior and different kinds of data. A comparative analysis of these algorithms has been performed.
{"title":"Plasma diagnostics using computed tomography method","authors":"N. Denisova","doi":"10.1109/PLASMA.2008.4591120","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4591120","url":null,"abstract":"Summary form only given. A review of applications of the tomographic method for diagnostics of various plasma objects has been performed in this work. The objects are: methane plasma evolution in plasma-chemical reactor, a capillary discharge of inner diameter of 1 mm, a high-pressure non-symmetrical arc plasma, a high frequency inductive coupled plasma. The computed tomography is receiving increasing attention as a powerful method for the reconstruction of the local characteristics in both: high-temperature and low-temperature plasma. Local plasma characteristics can be derived from the integrated data by combining of an integrating measurement techniques and computer tomography algorithms and methods. This can provide much useful information on the plasma structure and its evolution in time. There are various theoretical approaches on the development of algorithms for obtaining tomographic images, such as algebraic reconstruction technique, maximum entropy method, minimum Fisher information algorithm, constrained optimization and maximum a posteriori methods. These algorithms are intended to be applied in different class of reconstruction problems corresponding to different kinds of prior and different kinds of data. A comparative analysis of these algorithms has been performed.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"62 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83435665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-06-15DOI: 10.1109/PLASMA.2008.4591088
Xie Peilin, Tu Yan
Summary form only given. The weak discharge during the reset ramp period plays an important part in lowering the background luminance and improving contrast ratio of plasma display panel (PDP). In order to reduce the reset discharge intensity while keeping proper addressing state, influence of the reset waveform has been studied for the novel shadow mask PDP (SMPDP) in this paper. The discharge process of different ramp waveforms was investigated by both simulation and experiment methods. In the experiment, the test panel was lightened in the form of isolated pixels. Results showed that the background luminance and contrast ratio of SMPDP can be improved greatly after optimizing the reset ramp waveform. According to the results, the pulses of weak discharge were separate with each other, and the first weak discharge pulse was stronger than others. The intensity of the reset discharge decreased with the reduction of the slope while the number of the weak discharge increased. The discharge became weaker as the ramp-up voltage rose while the slope was fixed, and the number of the weak discharge pulses increased, which ensured to form proper wall voltage. Address delay time was also studied with various reset waveforms during a reset period. The simulation results coincided well with the results that got from the experiment. Accordingly, a proper ramp waveform could be found for SMPDP.
{"title":"A study on the discharge from various ramp waveforms in shadow mask plasma display panel","authors":"Xie Peilin, Tu Yan","doi":"10.1109/PLASMA.2008.4591088","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4591088","url":null,"abstract":"Summary form only given. The weak discharge during the reset ramp period plays an important part in lowering the background luminance and improving contrast ratio of plasma display panel (PDP). In order to reduce the reset discharge intensity while keeping proper addressing state, influence of the reset waveform has been studied for the novel shadow mask PDP (SMPDP) in this paper. The discharge process of different ramp waveforms was investigated by both simulation and experiment methods. In the experiment, the test panel was lightened in the form of isolated pixels. Results showed that the background luminance and contrast ratio of SMPDP can be improved greatly after optimizing the reset ramp waveform. According to the results, the pulses of weak discharge were separate with each other, and the first weak discharge pulse was stronger than others. The intensity of the reset discharge decreased with the reduction of the slope while the number of the weak discharge increased. The discharge became weaker as the ramp-up voltage rose while the slope was fixed, and the number of the weak discharge pulses increased, which ensured to form proper wall voltage. Address delay time was also studied with various reset waveforms during a reset period. The simulation results coincided well with the results that got from the experiment. Accordingly, a proper ramp waveform could be found for SMPDP.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"28 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87337220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper reports on a special designed room temperature plasma jet device. The device, which can be driven by an AC or pulsed DC power supply, is capable of generating a helium plasma plume up to 11 cm long in the surrounding air. The safety of the device is evaluated by a simple electrical model. The device can be hand held and the plasma plume can be directed to any object to be treated. The rotational and vibrational temperatures of the plasma plume are measured to be about 300 K and 2300 K, respectively. The I-V characteristics of the plasma are discussed. The emission behavior of the plasma plume is studied. The absolute concentrations of several active species are measured and the effect of the plasma plume on bacterial are investigated.
{"title":"A long atmospheric pressure cold plasma plume for biomedical applications","authors":"Xinpei Lu, Q. Xiong, ZhiYuan Tang, Zhonghe Jiang, Xi-Wei Hu, Yuan Pan","doi":"10.1109/PLASMA.2008.4590777","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4590777","url":null,"abstract":"This paper reports on a special designed room temperature plasma jet device. The device, which can be driven by an AC or pulsed DC power supply, is capable of generating a helium plasma plume up to 11 cm long in the surrounding air. The safety of the device is evaluated by a simple electrical model. The device can be hand held and the plasma plume can be directed to any object to be treated. The rotational and vibrational temperatures of the plasma plume are measured to be about 300 K and 2300 K, respectively. The I-V characteristics of the plasma are discussed. The emission behavior of the plasma plume is studied. The absolute concentrations of several active species are measured and the effect of the plasma plume on bacterial are investigated.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"26 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90556517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-06-15DOI: 10.1109/PLASMA.2008.4590788
V. Engelko, G. Mueller
A review of investigations on generation and transport of pulsed intense electron beams of microsecond duration is presented. For production of the beams multipoint explosive emission cathodes are used. The cathode design allows to produce homogeneous and stable plasma layers of different geometry with an area of up to 104 cm2. By using the multipoint cathodes planar, cylindrical, tubular and radial electron beams were produced. Investigation of the electron beams generation, transport in vacuum and interaction with different target materials are described. Examples of microsecond intense electron beams applications are given.
{"title":"Generation and transport of pulsed intense electron beams of microsecond duration","authors":"V. Engelko, G. Mueller","doi":"10.1109/PLASMA.2008.4590788","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4590788","url":null,"abstract":"A review of investigations on generation and transport of pulsed intense electron beams of microsecond duration is presented. For production of the beams multipoint explosive emission cathodes are used. The cathode design allows to produce homogeneous and stable plasma layers of different geometry with an area of up to 104 cm2. By using the multipoint cathodes planar, cylindrical, tubular and radial electron beams were produced. Investigation of the electron beams generation, transport in vacuum and interaction with different target materials are described. Examples of microsecond intense electron beams applications are given.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"8 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86665085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-06-15DOI: 10.1109/PLASMA.2008.4590794
V. Tarasenko, E. H. Baksht, A. G. Burachenko, I. Kostyrya, M. Lomaev, D. Rybka
In this paper, the recent measurement results on duration and amplitude of a beam, generated at a nanosecond discharge in different gases have been summarized. Voltage pulses ~25, ~150 and ~250 kV in amplitude were applied to the gas gap with inhomogeneous electric field. Discharge formation and super short avalanche electrons beam (SAEB) generation in sulfur hexafluoride and xenon at pressure of 0.01-2.5 atm and helium of 10-4-12 atm have been investigated. The beam of runaway electrons behind 45 mum Al-Be foil was observed at sulfur hexafluoride and xenon pressure up to 2 atm. It was found that the SAEB duration (FWHM) increased with sulfur hexafluoride pressure in the range 1-2.5 atm. Spectra of a diffuse and contracted discharges in sulfur hexafluoride are presented. Waveforms of the electrons beams generated in helium at pressure 10-4-12 atm were registered. Therewith the electrons beam in helium at p = 12 atm was obtained for the first time. Complex dependence of the electrons beam current amplitude from helium pressure was obtained. Three peaks of the current were observed at pressure 0.01, ~0.07 and ~3 atm. It is presented that at SAEB current recording through a region with a small diameter the pulse duration behind a foil over the gas diode axis is no more than 90 ps. For recording, the pulse shape it is necessary to use a small-sized coaxial collector, loaded to a high-frequency cable, and the same collector is used for taking the discharge density distribution over the foil surface in order to determine the SAEB amplitude. The electron distribution over the foil section should be compared with a per pulse distribution. In these experiments, we have compared the distributions obtained per pulse on a RF-3 and luminophore films, placed behind a foil. Besides that, intensity distribution of X-ray radiation at the gas diode output was recorded by using a multi-channel detection device based on microstrip arsenide-gallium detectors of ionizing radiation. An analysis of those data shows that at the beam current duration (FWHM) of ~90 ps the beam current amplitude behind the 10-mum thickness Al-foil at atmospheric pressure of air is ~50 A.
{"title":"Generation of supershort avalanche electron beams in nanosecond discharges in high-pressure gases","authors":"V. Tarasenko, E. H. Baksht, A. G. Burachenko, I. Kostyrya, M. Lomaev, D. Rybka","doi":"10.1109/PLASMA.2008.4590794","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4590794","url":null,"abstract":"In this paper, the recent measurement results on duration and amplitude of a beam, generated at a nanosecond discharge in different gases have been summarized. Voltage pulses ~25, ~150 and ~250 kV in amplitude were applied to the gas gap with inhomogeneous electric field. Discharge formation and super short avalanche electrons beam (SAEB) generation in sulfur hexafluoride and xenon at pressure of 0.01-2.5 atm and helium of 10-4-12 atm have been investigated. The beam of runaway electrons behind 45 mum Al-Be foil was observed at sulfur hexafluoride and xenon pressure up to 2 atm. It was found that the SAEB duration (FWHM) increased with sulfur hexafluoride pressure in the range 1-2.5 atm. Spectra of a diffuse and contracted discharges in sulfur hexafluoride are presented. Waveforms of the electrons beams generated in helium at pressure 10-4-12 atm were registered. Therewith the electrons beam in helium at p = 12 atm was obtained for the first time. Complex dependence of the electrons beam current amplitude from helium pressure was obtained. Three peaks of the current were observed at pressure 0.01, ~0.07 and ~3 atm. It is presented that at SAEB current recording through a region with a small diameter the pulse duration behind a foil over the gas diode axis is no more than 90 ps. For recording, the pulse shape it is necessary to use a small-sized coaxial collector, loaded to a high-frequency cable, and the same collector is used for taking the discharge density distribution over the foil surface in order to determine the SAEB amplitude. The electron distribution over the foil section should be compared with a per pulse distribution. In these experiments, we have compared the distributions obtained per pulse on a RF-3 and luminophore films, placed behind a foil. Besides that, intensity distribution of X-ray radiation at the gas diode output was recorded by using a multi-channel detection device based on microstrip arsenide-gallium detectors of ionizing radiation. An analysis of those data shows that at the beam current duration (FWHM) of ~90 ps the beam current amplitude behind the 10-mum thickness Al-foil at atmospheric pressure of air is ~50 A.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"7 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79655598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-06-15DOI: 10.1109/PLASMA.2008.4590975
K. Arshak, I. Guiney, O. Korostynska, E. Forde
Summary form only given. A novel multi-electrode dielectric barrier discharge (DBD) plasma system exhibiting active species gain is examined for the production of ozone gas and hence microelectronic substrate treatment. This species gain is achieved by having four electrode pairs in a vertical arrangement and supplying compressed air to traverse throughout the system. This forces the filamentary striations together through lateral pressure, thus aiding in the formation of an extremely dense plasma. The multi-electrode system operates in an effective feed-forward mechanism to create a denser plasma than reported previously. By increasing the initial conditions for oxygen metastables and radicals, singlet oxygen atoms and other reactive species, the overall density is also increased for successive electrode pairs. Additionally, existing plasma technologies for ozone production require the sample to be treated within the plasma volume. Due to the forced nature of the plasma flow, indirect treatment is possible and all results reported here are based on this. Tests on mica and silicon for the semiconductor industries were performed and compared with existing ozone treatment technologies. Results indicate that sufficient surface chemical changes were in evidence with only 30 seconds of plasma treatment. These were obtained by microscopic analysis using scanning electron microscopy (SEM) and Raman spectroscopy in addition to contact angle/wickability tests. These results compare excellently with standard 45-minute treatments of existing technology indicating that this novel plasma system could be used to produce similar quantities of ozone in roughly 1.1% of the time to standard ozone treatment apparatus. In particular this research has enormous potential in industry due to the high concentration of ozone produced coupled with the prospective in-line set-up of the system. Microelectronic sensors were fabricated from these substrates and functioned in a similar manner to existing sensors, i.e. with almost 45 minutes cut from the manufacture time.
{"title":"Dielectric barrier discharge species gain for microelectronic substrate treatment","authors":"K. Arshak, I. Guiney, O. Korostynska, E. Forde","doi":"10.1109/PLASMA.2008.4590975","DOIUrl":"https://doi.org/10.1109/PLASMA.2008.4590975","url":null,"abstract":"Summary form only given. A novel multi-electrode dielectric barrier discharge (DBD) plasma system exhibiting active species gain is examined for the production of ozone gas and hence microelectronic substrate treatment. This species gain is achieved by having four electrode pairs in a vertical arrangement and supplying compressed air to traverse throughout the system. This forces the filamentary striations together through lateral pressure, thus aiding in the formation of an extremely dense plasma. The multi-electrode system operates in an effective feed-forward mechanism to create a denser plasma than reported previously. By increasing the initial conditions for oxygen metastables and radicals, singlet oxygen atoms and other reactive species, the overall density is also increased for successive electrode pairs. Additionally, existing plasma technologies for ozone production require the sample to be treated within the plasma volume. Due to the forced nature of the plasma flow, indirect treatment is possible and all results reported here are based on this. Tests on mica and silicon for the semiconductor industries were performed and compared with existing ozone treatment technologies. Results indicate that sufficient surface chemical changes were in evidence with only 30 seconds of plasma treatment. These were obtained by microscopic analysis using scanning electron microscopy (SEM) and Raman spectroscopy in addition to contact angle/wickability tests. These results compare excellently with standard 45-minute treatments of existing technology indicating that this novel plasma system could be used to produce similar quantities of ozone in roughly 1.1% of the time to standard ozone treatment apparatus. In particular this research has enormous potential in industry due to the high concentration of ozone produced coupled with the prospective in-line set-up of the system. Microelectronic sensors were fabricated from these substrates and functioned in a similar manner to existing sensors, i.e. with almost 45 minutes cut from the manufacture time.","PeriodicalId":6359,"journal":{"name":"2008 IEEE 35th International Conference on Plasma Science","volume":"42 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2008-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77301872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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