Pub Date : 2014-04-22DOI: 10.1109/IVEC.2014.6857502
A. Soane, E. Nanni, M. Shapiro, R. Temkin, Hae-Gun Kim
We report on the progress of a 140 GHz pulsed gyro-amplifier system being developed at MIT for enhanced Dynamic Nuclear Polarization for NMR (DNP-NMR). A confocal geometry configuration is being studied as an approach to an overmoded interaction waveguide. The new amplifier differs from a previous version by incorporating improvements to structural construction, optimized input coupling, and sever design1. The confocal geometry consists of two curved mirrors spaced equal to their radii of curvature (R = L = 6.8 mm, width = 5 mm). The operating frequency of 140 GHz is supported by the higher-order HE06 mode. In order to suppress lower-order modes, the confocal geometry has open sides to allow radiation to leak out of the confined structure. By an appropriate design of the confocal parameters, these lower-order modes should have a greater loss per unit length than the mode of operation. The two severs (length 2.51cm, minimum width 0.74 mm) help to prevent oscillations by providing high attenuation within the waveguide.
我们报告了麻省理工学院正在开发的用于增强核磁共振动态核极化(DNP-NMR)的140 GHz脉冲陀螺仪放大器系统的进展。研究了一种共焦几何结构，作为一种超模相互作用波导的方法。新的放大器不同于以前的版本，包括改进结构结构，优化输入耦合和服务器设计1。共焦几何结构由两个弯曲镜组成，它们的间距等于它们的曲率半径(R = L = 6.8 mm，宽度= 5 mm)。高阶HE06模式支持140ghz工作频率。为了抑制低阶模式，共聚焦几何形状具有开放的侧面，以允许辐射从受限结构中泄漏出来。通过适当的共焦参数设计，这些低阶模式应该比工作模式有更大的单位长度损耗。两个伺服器(长度2.51cm，最小宽度0.74 mm)通过在波导内提供高衰减来帮助防止振荡。
{"title":"Progress of 140 GHz gyro-amplifier using confocal waveguide","authors":"A. Soane, E. Nanni, M. Shapiro, R. Temkin, Hae-Gun Kim","doi":"10.1109/IVEC.2014.6857502","DOIUrl":"https://doi.org/10.1109/IVEC.2014.6857502","url":null,"abstract":"We report on the progress of a 140 GHz pulsed gyro-amplifier system being developed at MIT for enhanced Dynamic Nuclear Polarization for NMR (DNP-NMR). A confocal geometry configuration is being studied as an approach to an overmoded interaction waveguide. The new amplifier differs from a previous version by incorporating improvements to structural construction, optimized input coupling, and sever design1. The confocal geometry consists of two curved mirrors spaced equal to their radii of curvature (R = L = 6.8 mm, width = 5 mm). The operating frequency of 140 GHz is supported by the higher-order HE06 mode. In order to suppress lower-order modes, the confocal geometry has open sides to allow radiation to leak out of the confined structure. By an appropriate design of the confocal parameters, these lower-order modes should have a greater loss per unit length than the mode of operation. The two severs (length 2.51cm, minimum width 0.74 mm) help to prevent oscillations by providing high attenuation within the waveguide.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87740234","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 : 2013-10-17DOI: 10.1109/PLASMA.2013.6634795
M. Schneider, M. Schalnat, J. Macdonald, S. Doty, E. Bagdy, N. Keller, J. Ennis
Summary form only given. There is a significant need for high temperature capacitors for a variety of operating conditions including pulse power, and high frequency power conditioning applications at temperatures between 125°C and 200°C. Here we cover several new developments in high temperature capacitor technologies presenting results on thin film capacitors useful for long life, high energy density, and high reliability. Additionally, results are presented on an improved very-high temperature film (200°C and higher) with more reliable self-healing, longer lifetime, and higher energy densities. Results from metallized film capacitors with improved termination demonstrating drastic improvements in current carrying capabilities in both CW RMS current and peak pulse current regimes are also presented. Finally, a theoretical high temperature capacitor utilizing a combination of these technologies is discussed and compared to existing COTS and SOTA capacitors.
{"title":"High current, high temperature capacitors: Recent developments and future prospects","authors":"M. Schneider, M. Schalnat, J. Macdonald, S. Doty, E. Bagdy, N. Keller, J. Ennis","doi":"10.1109/PLASMA.2013.6634795","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6634795","url":null,"abstract":"Summary form only given. There is a significant need for high temperature capacitors for a variety of operating conditions including pulse power, and high frequency power conditioning applications at temperatures between 125°C and 200°C. Here we cover several new developments in high temperature capacitor technologies presenting results on thin film capacitors useful for long life, high energy density, and high reliability. Additionally, results are presented on an improved very-high temperature film (200°C and higher) with more reliable self-healing, longer lifetime, and higher energy densities. Results from metallized film capacitors with improved termination demonstrating drastic improvements in current carrying capabilities in both CW RMS current and peak pulse current regimes are also presented. Finally, a theoretical high temperature capacitor utilizing a combination of these technologies is discussed and compared to existing COTS and SOTA capacitors.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77571198","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 : 2013-10-17DOI: 10.1109/PLASMA.2013.6635144
R. Xu, Jue Wang, C. Ren, Ying Zhao, P. Yan
Surface characteristics of Insulator effect its surface flashover performance obviously, appropriate surface treatment can increase the surface flashover voltage. Ion implantation technology is an effective surface modification tool, it can change the roughness, resistivity and adsorbability on the insulator surface. Polytetrafluoroethylene (PTFE) was modified by C ion and nitrogen ion by using a electron cyclotron resonance (ECR) ion source. The surface flashover voltage were measured on the experimental platforms of surface characteristics in vacuum before and after modification, Also the characteristies and microstructure of the implanted layer were studied by using the SEM and XPS and find the influencing factors on surface flashover properties of PTFE modified by ion implantation.
{"title":"Research on surface flashover properties of polytetrafluoroethylene modified by ion implantation","authors":"R. Xu, Jue Wang, C. Ren, Ying Zhao, P. Yan","doi":"10.1109/PLASMA.2013.6635144","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6635144","url":null,"abstract":"Surface characteristics of Insulator effect its surface flashover performance obviously, appropriate surface treatment can increase the surface flashover voltage. Ion implantation technology is an effective surface modification tool, it can change the roughness, resistivity and adsorbability on the insulator surface. Polytetrafluoroethylene (PTFE) was modified by C ion and nitrogen ion by using a electron cyclotron resonance (ECR) ion source. The surface flashover voltage were measured on the experimental platforms of surface characteristics in vacuum before and after modification, Also the characteristies and microstructure of the implanted layer were studied by using the SEM and XPS and find the influencing factors on surface flashover properties of PTFE modified by ion implantation.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86957153","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 : 2013-10-17DOI: 10.1109/PLASMA.2013.6634917
L. Musson, M. Hopkins, P. Stoltz, C. Roark
A common phenomenon in plasma transport is ambipolar expansion; the ambipolar expansion rate is the typical rate at which a neutral plasma will expand into a vacuum. This expansion is particularly important, for example, in understanding how quickly a plasma will fill a gap in high power electronics or in understanding how energy is transported in intense laser-driven plasmas. Often times, a plasma simulation must accurately capture the ambipolar expansion of a neutral plasma. We present simulation benchmarks for three codes: one plasma fluid code1 and two kinetic plasma codes - one of the kinetic codes using an unstructured mesh and the other a structured mesh. We compare results from these codes to analytic models and previously published simulation results. We discuss speed and accuracy for these three different approaches, specifically including a discussion of particle splitting and combining algorithms in the kinetic approaches.
{"title":"Solution comparisons of models of an expanding ambipolar plasma","authors":"L. Musson, M. Hopkins, P. Stoltz, C. Roark","doi":"10.1109/PLASMA.2013.6634917","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6634917","url":null,"abstract":"A common phenomenon in plasma transport is ambipolar expansion; the ambipolar expansion rate is the typical rate at which a neutral plasma will expand into a vacuum. This expansion is particularly important, for example, in understanding how quickly a plasma will fill a gap in high power electronics or in understanding how energy is transported in intense laser-driven plasmas. Often times, a plasma simulation must accurately capture the ambipolar expansion of a neutral plasma. We present simulation benchmarks for three codes: one plasma fluid code1 and two kinetic plasma codes - one of the kinetic codes using an unstructured mesh and the other a structured mesh. We compare results from these codes to analytic models and previously published simulation results. We discuss speed and accuracy for these three different approaches, specifically including a discussion of particle splitting and combining algorithms in the kinetic approaches.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76735799","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 : 2013-10-17DOI: 10.1109/PLASMA.2013.6635012
S. Patel, D. Chalenski, A. Steiner, D. Yager-Elorriaga, R. Gilgenbach, Y. Lau, N. Jordan
Summary form only given. X-pinch experiments are underway on the MAIZE Linear Transformer Driver (LTD) at the University of Michigan. The MAIZE LTD can supply 1 MA, 100 kV pulses with 100 ns risetime into a matched load. The x-pinch consists of a single 35-50 μm Al or Mo wire separated by conical electrodes, between two current return plates. The LTD is charged to +/-70 kV resulting in approximately 0.4-0.5 MA through the wire. Initial tests show multiple x-ray bursts over the length of the current pulse.The x-pinch will ultimately backlight the Magneto RayleighTaylor (MRT) instability on a planar Al foil. The foil load contains a 1 cm wide, 400 nm thick foil placed between two current return plates. Ongoing MRT experiments involve seeding the MRT instability with arrays of 30 micron holes micromachined in the foil by a 150 fs Ti:sapphire laser. Laser shadowgraphy has previously been used to image the seeded foil as well as determine the MRT growth rate.[1,2] Future plans for the x-pinch include placing it in parallel with the foil in order to more accurately image and characterize the MRT instability. Plans for a smaller 100-150 kA compact pinch driver are also in development; (see poster by YagerEliorraga at this conference).
{"title":"Foil MRT and X-pinch experiments on a MA linear transformer driver","authors":"S. Patel, D. Chalenski, A. Steiner, D. Yager-Elorriaga, R. Gilgenbach, Y. Lau, N. Jordan","doi":"10.1109/PLASMA.2013.6635012","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6635012","url":null,"abstract":"Summary form only given. X-pinch experiments are underway on the MAIZE Linear Transformer Driver (LTD) at the University of Michigan. The MAIZE LTD can supply 1 MA, 100 kV pulses with 100 ns risetime into a matched load. The x-pinch consists of a single 35-50 μm Al or Mo wire separated by conical electrodes, between two current return plates. The LTD is charged to +/-70 kV resulting in approximately 0.4-0.5 MA through the wire. Initial tests show multiple x-ray bursts over the length of the current pulse.The x-pinch will ultimately backlight the Magneto RayleighTaylor (MRT) instability on a planar Al foil. The foil load contains a 1 cm wide, 400 nm thick foil placed between two current return plates. Ongoing MRT experiments involve seeding the MRT instability with arrays of 30 micron holes micromachined in the foil by a 150 fs Ti:sapphire laser. Laser shadowgraphy has previously been used to image the seeded foil as well as determine the MRT growth rate.[1,2] Future plans for the x-pinch include placing it in parallel with the foil in order to more accurately image and characterize the MRT instability. Plans for a smaller 100-150 kA compact pinch driver are also in development; (see poster by YagerEliorraga at this conference).","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90157742","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 : 2013-10-17DOI: 10.1109/PLASMA.2013.6633178
J. Feugeas, P. Nicolai, M. Touati, J. Breil, B. Dubroca, X. Ribeyre, J. Santos, V. Tikhonchuk, S. Gus'kov
Summary form only given. One major issue to address in Inertial Confinement Fusion (ICF) is the detailed description of the kinetic transport of laser generated fast electrons in the time and space scales of the hydrodynamic evolution of the imploded target. We have developed, at CELIA, a fast reduced kinetic model for relativistic electrons transport based on the angular moments of the relativistic Fokker-Planck equation, the M1 model1. This model takes into account the slowing down of fast electrons through collisions with plasma electrons (free and bounded), plasmons and the elastic scattering of fast electrons on plasma ions and electrons. The self-consistent magnetic and electric fields are computed thanks to a generalized Ohm law. This module has been implemented into the 2D radiation hydrodynamic code CHIC2. The M1 model is used as well as for the Fast Ignition (FI) than for the Shock Ignition (SI) schemes. A recent experiment of relativistic electrons transport through Aluminum foils is analyzed thanks to this multi-scales tool. Because of its computing speed, various initial configurations have been tested to reproduce experimental data. In addition, due to its structure, the effects of electric and magnetic fields can easily be highlighted and so the resistive fast electrons losses are directly compared to the collisional losses. Concerning Shock Ignition scheme, it is shown that the energy transfer by fast electrons from the corona to the compressed shell is a important mechanism in the creation of ablation pressure. A 30 keV energy electron beam of 2 - 5 PW/cm2 energy flux may create a pressure amplitude of more than 300 Mbar within few tens of ps in a precompressed solid material3. The dynamics of the ablation layer and the shock evolution are also presented in realistic configurations.
{"title":"PPPS-2013: New fast and accurate numerical method for laser-produced relativistic electrons beams transport in the context of ICF — Applications to fast and shock ignition","authors":"J. Feugeas, P. Nicolai, M. Touati, J. Breil, B. Dubroca, X. Ribeyre, J. Santos, V. Tikhonchuk, S. Gus'kov","doi":"10.1109/PLASMA.2013.6633178","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633178","url":null,"abstract":"Summary form only given. One major issue to address in Inertial Confinement Fusion (ICF) is the detailed description of the kinetic transport of laser generated fast electrons in the time and space scales of the hydrodynamic evolution of the imploded target. We have developed, at CELIA, a fast reduced kinetic model for relativistic electrons transport based on the angular moments of the relativistic Fokker-Planck equation, the M1 model1. This model takes into account the slowing down of fast electrons through collisions with plasma electrons (free and bounded), plasmons and the elastic scattering of fast electrons on plasma ions and electrons. The self-consistent magnetic and electric fields are computed thanks to a generalized Ohm law. This module has been implemented into the 2D radiation hydrodynamic code CHIC2. The M1 model is used as well as for the Fast Ignition (FI) than for the Shock Ignition (SI) schemes. A recent experiment of relativistic electrons transport through Aluminum foils is analyzed thanks to this multi-scales tool. Because of its computing speed, various initial configurations have been tested to reproduce experimental data. In addition, due to its structure, the effects of electric and magnetic fields can easily be highlighted and so the resistive fast electrons losses are directly compared to the collisional losses. Concerning Shock Ignition scheme, it is shown that the energy transfer by fast electrons from the corona to the compressed shell is a important mechanism in the creation of ablation pressure. A 30 keV energy electron beam of 2 - 5 PW/cm2 energy flux may create a pressure amplitude of more than 300 Mbar within few tens of ps in a precompressed solid material3. The dynamics of the ablation layer and the shock evolution are also presented in realistic configurations.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91426887","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 : 2013-10-17DOI: 10.1109/PLASMA.2013.6633486
B. Qiao
Intense MeV proton beams have applications in medicine, material science and inertial fusion energy (IFE). Laser-accelerated proton beams can be generated and focused to exceptionally high intensities that are beneficial for these applications, especially proton fast ignition (pFI). In pFI, a focused proton beam with energy 20kJ, diameter <;40μm and mean energy of 10MeV needs to be produced from a hemisphere target and pass through the cone tip and surrounding plasma efficiently without distortion.
{"title":"Acceleration and transport of a focused laser-generated proton beams for fast-ignition","authors":"B. Qiao","doi":"10.1109/PLASMA.2013.6633486","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633486","url":null,"abstract":"Intense MeV proton beams have applications in medicine, material science and inertial fusion energy (IFE). Laser-accelerated proton beams can be generated and focused to exceptionally high intensities that are beneficial for these applications, especially proton fast ignition (pFI). In pFI, a focused proton beam with energy 20kJ, diameter <;40μm and mean energy of 10MeV needs to be produced from a hemisphere target and pass through the cone tip and surrounding plasma efficiently without distortion.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85438253","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 : 2013-10-17DOI: 10.1109/PLASMA.2013.6633508
Peng Zhang, Y. Lau
Summary form only given. Electrical contact is an important issue to high power microwave sources, pulsed power systems, field emitters, thin film devices and integrated circuits, and interconnects, etc. Current crowding, which leads to intense local heating, is a well known phenomenon associated with contact resistance for the above areas. This paper summarizes recent development on the accurate evaluation of contact resistance for both horizontal [1-3] and vertical [3,4] contacts. By horizontal (vertical), we mean a current flow that is parallel (perpendicular) to the base of a contact member. The contact members may possess vastly different electrical resistivities, and arbitrary aspect ratios. The analytic calculations are validated by the MAXWELL codes. Current partitions in different regions are displayed. Current crowding is shown to occur within a distance of 0.44h of the rim of an electrode that is made in horizontal contact with a thin film of thickness h, regardless of the electrode shape [1,3]. A novel relation between AC bulk contact resistance and DC thin film contact resistance was discovered [3]. General scaling laws are presented.
{"title":"Recent development on the modeling of electrical contact","authors":"Peng Zhang, Y. Lau","doi":"10.1109/PLASMA.2013.6633508","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633508","url":null,"abstract":"Summary form only given. Electrical contact is an important issue to high power microwave sources, pulsed power systems, field emitters, thin film devices and integrated circuits, and interconnects, etc. Current crowding, which leads to intense local heating, is a well known phenomenon associated with contact resistance for the above areas. This paper summarizes recent development on the accurate evaluation of contact resistance for both horizontal [1-3] and vertical [3,4] contacts. By horizontal (vertical), we mean a current flow that is parallel (perpendicular) to the base of a contact member. The contact members may possess vastly different electrical resistivities, and arbitrary aspect ratios. The analytic calculations are validated by the MAXWELL codes. Current partitions in different regions are displayed. Current crowding is shown to occur within a distance of 0.44h of the rim of an electrode that is made in horizontal contact with a thin film of thickness h, regardless of the electrode shape [1,3]. A novel relation between AC bulk contact resistance and DC thin film contact resistance was discovered [3]. General scaling laws are presented.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75162586","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6634979
P. Liu, T. Grotjohn
Summary form only given. Portable low cost microplasma sources are of interest for various applications such as materials processing, treatment of biomedical materials, chemical analysis and optical radiation sources. Microplasma sources are especially of interest for atmospheric pressure operation because they do not require a vacuum system. Further, by using higher frequency energy (microwave) to power the microplasma discharge, erosion of electrodes is reduced or essentially eliminated. Another feature of microplasmas is the high power density and plasma density of the discharges. Additionally, the gas temperature of microdischarges is lower than larger plasmas at atmospheric pressure. In this investigation a microwave powered microplasma system based on a double-strip-line structure is developed for the generation of atmospheric pressure plasmas with various feed-gases and feed-gas mixtures. The microplasma system is constructed with the top and bottom copper strip-lines separated by a dielectric material. The strip-line structure is powered at one end and the plasma is formed at the other end where the two copper strip-lines are brought together to a gap with 250 microns separation. The feed-gas is flowed through a channel in the dielectric such that it exits with the feed-gas flowing into the gap created by the two strip-lines. The gas flow channel in the dielectric is 250 microns high by 6 mm wide. The flow rate is varied from 900-2400 sccm. Argon and argon-oxygen microplasma discharges are formed in the gap between the two copper strip-lines. In argon-oxygen plasmas investigated, the oxygen percentage is varied from 1% up to 5%. The microwave power used for the discharges varies from 5 to 60 Watts. Images of the plasma are taken to show the shape, volume and intensity of the microplasmas. Optical emission spectroscopy is used to diagnose the discharges. The emissions from selected excited atomic and molecular oxygen species are measured. Other properties of the microplasma including gas temperature and electron temperature are also measured. Some experiments of etching diamond with argon-oxygen microdischarges will be presented.
{"title":"Atmospheric pressure microwave-powered microplasma source based on strip-line structure","authors":"P. Liu, T. Grotjohn","doi":"10.1109/PLASMA.2013.6634979","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6634979","url":null,"abstract":"Summary form only given. Portable low cost microplasma sources are of interest for various applications such as materials processing, treatment of biomedical materials, chemical analysis and optical radiation sources. Microplasma sources are especially of interest for atmospheric pressure operation because they do not require a vacuum system. Further, by using higher frequency energy (microwave) to power the microplasma discharge, erosion of electrodes is reduced or essentially eliminated. Another feature of microplasmas is the high power density and plasma density of the discharges. Additionally, the gas temperature of microdischarges is lower than larger plasmas at atmospheric pressure. In this investigation a microwave powered microplasma system based on a double-strip-line structure is developed for the generation of atmospheric pressure plasmas with various feed-gases and feed-gas mixtures. The microplasma system is constructed with the top and bottom copper strip-lines separated by a dielectric material. The strip-line structure is powered at one end and the plasma is formed at the other end where the two copper strip-lines are brought together to a gap with 250 microns separation. The feed-gas is flowed through a channel in the dielectric such that it exits with the feed-gas flowing into the gap created by the two strip-lines. The gas flow channel in the dielectric is 250 microns high by 6 mm wide. The flow rate is varied from 900-2400 sccm. Argon and argon-oxygen microplasma discharges are formed in the gap between the two copper strip-lines. In argon-oxygen plasmas investigated, the oxygen percentage is varied from 1% up to 5%. The microwave power used for the discharges varies from 5 to 60 Watts. Images of the plasma are taken to show the shape, volume and intensity of the microplasmas. Optical emission spectroscopy is used to diagnose the discharges. The emissions from selected excited atomic and molecular oxygen species are measured. Other properties of the microplasma including gas temperature and electron temperature are also measured. Some experiments of etching diamond with argon-oxygen microdischarges will be presented.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73525466","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 : 2013-06-16DOI: 10.1109/PLASMA.2013.6635127
S. J. Pendleton, A. Kuthi, Hao Chen Martin A. Gundersen, P. Muggli
Summary form only given. Reported are new results for pulsed power-driven hollow cathode hydrogen-based plasma source development, needed for plasma-based accelerator experiments, including particle-beam-driven plasma wakefield accelerators. Capillary sources have been constructed of transparent cylindrical borosilicate glass tubes in lengths up to 15 cm and inner diameters up to 2 mm. The plasma discharge is presently driven by a thyratron-switched pulse forming network and step-up transformer. Uniform plasma densities of over 1018 cm-3 have been demonstrated, and the length and density can be readily varied for optimal performance. The pulsed power requirements for increasing capillary size and optimization of solid-state pulsed power switching for the purpose of increased flexibility, energy minimization and long life will be discussed. Time dependence of plasma density, and other variations of the device parameters for fine-tuning of accelerator applications is analyzed and discussed, including the use of this discharge at accelerator facilities for plasma wakefield experiments.
{"title":"Pulsed high-density hydrogen plasma source for wakefield accelerator applications","authors":"S. J. Pendleton, A. Kuthi, Hao Chen Martin A. Gundersen, P. Muggli","doi":"10.1109/PLASMA.2013.6635127","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6635127","url":null,"abstract":"Summary form only given. Reported are new results for pulsed power-driven hollow cathode hydrogen-based plasma source development, needed for plasma-based accelerator experiments, including particle-beam-driven plasma wakefield accelerators. Capillary sources have been constructed of transparent cylindrical borosilicate glass tubes in lengths up to 15 cm and inner diameters up to 2 mm. The plasma discharge is presently driven by a thyratron-switched pulse forming network and step-up transformer. Uniform plasma densities of over 1018 cm-3 have been demonstrated, and the length and density can be readily varied for optimal performance. The pulsed power requirements for increasing capillary size and optimization of solid-state pulsed power switching for the purpose of increased flexibility, energy minimization and long life will be discussed. Time dependence of plasma density, and other variations of the device parameters for fine-tuning of accelerator applications is analyzed and discussed, including the use of this discharge at accelerator facilities for plasma wakefield experiments.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75506428","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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