Pub Date : 2013-06-16DOI: 10.1109/PLASMA.2013.6633313
L. Pickworth, S. Lebedev, F. Suzuki-Vidal, G. Swadling, G. Hall, S. Bland, M. Bennett, G. Burdiak, J. Skidmore, L. Suttle, P. de Grouchy, J. Chittenden, M. Bocchi, N. Niasse
Summary form only given. Experimental investigation of collisions of supersonic plasma jets with metal foils and head-on collisions of two jets will be presented. The jets are produced by ablation of thin Al foils driven by 1.4MA, 250ns current pulse in a radial foil z-pinch configuration<;sup>[1.2,<;/sup> <;sup>3]<;/sup>. The jets propagate with velocity of ~50-100km/s, have high degree of collimation (opening angle 2-5°) and are radiatively cooled (cooling time <;<; hydrodynamic times). Collisions of the jets with foils, as well as inter-jet collisions, create a system of strong shocks both in the central dense part of the jet and in the lower density halo plasma which surrounds the jet and moves with the same speed. The formed shock features are sustained for ~300ns, and are diagnosed with laser interferometry, optical and XUV imaging, and with Thomson scattering diagnostics. Interpretation of the results indicates that a dynamically significant magnetic fields are present in the system, balancing the ram pressure of the flow and supporting extended stationary shock structures. The results are relevant to the studies of astrophysical phenomena in the laboratory, in particular internal shocks in jets young stars, and accretion shocks, and for understanding of magnetized high energy density plasma flows.
{"title":"Experiments with colliding supersonic plasma jets on the magpie pulsed power facility","authors":"L. Pickworth, S. Lebedev, F. Suzuki-Vidal, G. Swadling, G. Hall, S. Bland, M. Bennett, G. Burdiak, J. Skidmore, L. Suttle, P. de Grouchy, J. Chittenden, M. Bocchi, N. Niasse","doi":"10.1109/PLASMA.2013.6633313","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633313","url":null,"abstract":"Summary form only given. Experimental investigation of collisions of supersonic plasma jets with metal foils and head-on collisions of two jets will be presented. The jets are produced by ablation of thin Al foils driven by 1.4MA, 250ns current pulse in a radial foil z-pinch configuration<;sup>[1.2,<;/sup> <;sup>3]<;/sup>. The jets propagate with velocity of ~50-100km/s, have high degree of collimation (opening angle 2-5°) and are radiatively cooled (cooling time <;<; hydrodynamic times). Collisions of the jets with foils, as well as inter-jet collisions, create a system of strong shocks both in the central dense part of the jet and in the lower density halo plasma which surrounds the jet and moves with the same speed. The formed shock features are sustained for ~300ns, and are diagnosed with laser interferometry, optical and XUV imaging, and with Thomson scattering diagnostics. Interpretation of the results indicates that a dynamically significant magnetic fields are present in the system, balancing the ram pressure of the flow and supporting extended stationary shock structures. The results are relevant to the studies of astrophysical phenomena in the laboratory, in particular internal shocks in jets young stars, and accretion shocks, and for understanding of magnetized high energy density plasma flows.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"32 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75184754","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.2013.6633333
R. Fetzer, W. An, A. Weisenburger, G. Mueller
Summary form only given. Intense pulsed electron beams are commonly used to improve mechanical properties of metal targets in near-surface regions or for surface alloying. In some cases, however, the intended property changes are accompanied by the development of surface roughness. The exact origin of this phenomenon is still under debate. In this work, the dynamics of the target surface layer in its melted stage is investigated experimentally and theoretically. The pulsed electron beam facility GESA at KIT is used to generate electron beams with power density 0.5-2 MW/cm2, electron energy 120 keV, and pulse duration up to 200 μs. Various fast in-situ optical diagnostic tools have been set up and successfully tested during treatment of stainless steel, copper, and aluminum targets. After this preceding work, a systematic investigation of the influence of various materials and of specific beam parameters on the surface layer dynamics is now performed. The experimental studies are accompanied by numerical simulations of heat transfer and melt motion and by theoretical considerations concerning the relevance of possible hydrodynamic instabilities.
{"title":"Target surface layer dynamics during application of intense electron beams","authors":"R. Fetzer, W. An, A. Weisenburger, G. Mueller","doi":"10.1109/PLASMA.2013.6633333","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633333","url":null,"abstract":"Summary form only given. Intense pulsed electron beams are commonly used to improve mechanical properties of metal targets in near-surface regions or for surface alloying. In some cases, however, the intended property changes are accompanied by the development of surface roughness. The exact origin of this phenomenon is still under debate. In this work, the dynamics of the target surface layer in its melted stage is investigated experimentally and theoretically. The pulsed electron beam facility GESA at KIT is used to generate electron beams with power density 0.5-2 MW/cm2, electron energy 120 keV, and pulse duration up to 200 μs. Various fast in-situ optical diagnostic tools have been set up and successfully tested during treatment of stainless steel, copper, and aluminum targets. After this preceding work, a systematic investigation of the influence of various materials and of specific beam parameters on the surface layer dynamics is now performed. The experimental studies are accompanied by numerical simulations of heat transfer and melt motion and by theoretical considerations concerning the relevance of possible hydrodynamic instabilities.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"5 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73076697","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.2013.6634840
S. Hofmann, K. van Gils, R. Brandenburg, P. Bruggeman, Bouke Boukema
The inactivation of bacteria suspended in liquids by an atmospheric pressure plasma is a complicated and yet not well understood process, due to several constituents of the “plasma cocktail” in the plasma/gas phase which can contribute to bacteria inactivation and the transport and chemistry processes of the created species in the liquid phase. To investigate the main players in the bacteria inactivation processes we use a RF atmospheric pressure plasma jet which is used for remote bacteria treatment. The plasma jet is constructed to allow accurate power measurements. Mass spectrometry, optical emission spectroscopy as well as electrical diagnostics have been used to investigate the amount of charged and reactive species and UV-emission reaching the water surface. We show that with the chosen treatment conditions, reactive species (ROS and RNS) concentrations and probably (V)UV emission are high enough to induce chemistry in the liquid phase leading to bacteria inactivation, while the electric field and charged particles are too low to induce observed effects. To further determine the role of the reactive species interaction within the liquid, nitrite, nitrate and hydrogen peroxide concentrations have been obtained by ion chromatography and colorimetric methods. Combined with measured and estimated values of the reactive species in the gas phase we use a 0D-solution kinetics model to calculate other species expected in the liquid phase and important for bacteria inactivation, which have not been measured. We show that the obtained concentrations of HNO2, ONOO and H2O2 are in the same range as reported values in literature of the minimum inhibitory and bactericidal concentrations.
{"title":"Evaluation of plasma induced liquid chemistry for bacteria treatment with a remote RF argon atmospheric pressure plasma jet","authors":"S. Hofmann, K. van Gils, R. Brandenburg, P. Bruggeman, Bouke Boukema","doi":"10.1109/PLASMA.2013.6634840","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6634840","url":null,"abstract":"The inactivation of bacteria suspended in liquids by an atmospheric pressure plasma is a complicated and yet not well understood process, due to several constituents of the “plasma cocktail” in the plasma/gas phase which can contribute to bacteria inactivation and the transport and chemistry processes of the created species in the liquid phase. To investigate the main players in the bacteria inactivation processes we use a RF atmospheric pressure plasma jet which is used for remote bacteria treatment. The plasma jet is constructed to allow accurate power measurements. Mass spectrometry, optical emission spectroscopy as well as electrical diagnostics have been used to investigate the amount of charged and reactive species and UV-emission reaching the water surface. We show that with the chosen treatment conditions, reactive species (ROS and RNS) concentrations and probably (V)UV emission are high enough to induce chemistry in the liquid phase leading to bacteria inactivation, while the electric field and charged particles are too low to induce observed effects. To further determine the role of the reactive species interaction within the liquid, nitrite, nitrate and hydrogen peroxide concentrations have been obtained by ion chromatography and colorimetric methods. Combined with measured and estimated values of the reactive species in the gas phase we use a 0D-solution kinetics model to calculate other species expected in the liquid phase and important for bacteria inactivation, which have not been measured. We show that the obtained concentrations of HNO2, ONOO and H2O2 are in the same range as reported values in literature of the minimum inhibitory and bactericidal concentrations.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"91 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74438099","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.2013.6635117
S. Prasad, C. Leach, C. J. Buchenauer, M. Fuks, E. Schamiloglu
The transparent cathode (TC) invented at the University of New Mexico (UNM) showed high output powers, high efficiency and stable operation in the 2pi-mode over a wide range of magnetic field compared to the solid cathode when tested in the standard A6 magnetron.
{"title":"PPPS-2013: UNM transparent cathode experiments revisited","authors":"S. Prasad, C. Leach, C. J. Buchenauer, M. Fuks, E. Schamiloglu","doi":"10.1109/PLASMA.2013.6635117","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6635117","url":null,"abstract":"The transparent cathode (TC) invented at the University of New Mexico (UNM) showed high output powers, high efficiency and stable operation in the 2pi-mode over a wide range of magnetic field compared to the solid cathode when tested in the standard A6 magnetron.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"6 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73668927","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.2013.6633506
J. Petillo, D. Panagos, K. Jensen
Summary form only given. We report on the incorporation of a model of field emitters based on a Point Charge Model (PCM)1 that allows for rapid and analytical representations of tip current, variation, and emission statistics and its implementation and usage in the MICHELLE Particle-In-Cell (PIC) code2 to model the impact of emission variation on current characteristics and emittance. Rather than cold field emission characterized by the Fowler Nordheim equation, a General Thermal-Field (GTF) emission model3 treats warm and hot field emission sources. We shall compare the increases in emittance and beam radius due to emission non-uniformity as modeled by assuming a LogNormal (LN) distribution of emitter geometries4. The consequences for high frequency devices shall be explored.
{"title":"PPPS-2013: Emittance and emission from arrays with statistical variation","authors":"J. Petillo, D. Panagos, K. Jensen","doi":"10.1109/PLASMA.2013.6633506","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633506","url":null,"abstract":"Summary form only given. We report on the incorporation of a model of field emitters based on a Point Charge Model (PCM)1 that allows for rapid and analytical representations of tip current, variation, and emission statistics and its implementation and usage in the MICHELLE Particle-In-Cell (PIC) code2 to model the impact of emission variation on current characteristics and emittance. Rather than cold field emission characterized by the Fowler Nordheim equation, a General Thermal-Field (GTF) emission model3 treats warm and hot field emission sources. We shall compare the increases in emittance and beam radius due to emission non-uniformity as modeled by assuming a LogNormal (LN) distribution of emitter geometries4. The consequences for high frequency devices shall be explored.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"8 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73711379","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/PPC.2013.6627633
D. Nelson, M. Berninger, P. Flores, Douglas E. Good, D. Henderson, K. Hogge, S. Huber, S. Lutz, S. E. Mitchell, R. Howe, C. V. Mitton, I. Molina, D. R. Bozman, S. Cordova, D. R. Mitchell, E. Ormond
The development of the rod pinch diode has lead to high resolution radiography used on contained explosive experiments. The rod pinch diodes use a small diameter anode rod, which extends through a cathode aperture. Electrons borne off the aperture edge can self-insulate and pinch onto the tip of the rod, creating an intense, small x-ray source. This source is utilized as the primary diagnostic on numerous experiments that include high-value, single-shot events. In such applications there is an emphasis on machine reliability, x-ray reproducibility, and x-ray quality. We have observed that an additional pinch occurs at the interface near the anode rod and the rod holder. This suggests that there are stray electrons emitted from the surfaces of the surrounding area. In this paper we present results of x-ray measurements using a pinhole camera. The camera geometry used is an upstream view 30° with respect to the diode centerline. This diagnostic will be employed to: (1) diagnose x-ray reproducibility and quality, and (2) investigate the effect of different diode configurations.
{"title":"X-ray pinhole camera measurements","authors":"D. Nelson, M. Berninger, P. Flores, Douglas E. Good, D. Henderson, K. Hogge, S. Huber, S. Lutz, S. E. Mitchell, R. Howe, C. V. Mitton, I. Molina, D. R. Bozman, S. Cordova, D. R. Mitchell, E. Ormond","doi":"10.1109/PPC.2013.6627633","DOIUrl":"https://doi.org/10.1109/PPC.2013.6627633","url":null,"abstract":"The development of the rod pinch diode has lead to high resolution radiography used on contained explosive experiments. The rod pinch diodes use a small diameter anode rod, which extends through a cathode aperture. Electrons borne off the aperture edge can self-insulate and pinch onto the tip of the rod, creating an intense, small x-ray source. This source is utilized as the primary diagnostic on numerous experiments that include high-value, single-shot events. In such applications there is an emphasis on machine reliability, x-ray reproducibility, and x-ray quality. We have observed that an additional pinch occurs at the interface near the anode rod and the rod holder. This suggests that there are stray electrons emitted from the surfaces of the surrounding area. In this paper we present results of x-ray measurements using a pinhole camera. The camera geometry used is an upstream view 30° with respect to the diode centerline. This diagnostic will be employed to: (1) diagnose x-ray reproducibility and quality, and (2) investigate the effect of different diode configurations.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"50 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73791453","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.2013.6634953
Y. Zhu, L. Ang
Summary form only given. Shot noise is the fluctuation in the electrical signal due to the discreteness of electron charges1. The deviation of the uncorrelated shot noise is normally given by the Fano factor. Ultrafast electron pulse with high rightness and coherence can be generated by illumination of a dc-based metallic field emitter with femtosecond laser pulses2. A nonequilibrium model based on Boltzmann's equation has been used to explain the electron emission process3. Based on this model, the shot noise of the emission current is calculated. The effects of the shot noise reduction on applied dc voltage, laser intensity, pulse duration and metal work function are investigated. It is found that the Fano factor increases with small applied dc voltage, large laser field and longer time of tip and pulse interaction4. Our result would be helpful for investigate the coherence properties of ultrafast electron sources.
{"title":"Nonequilibrium effect for shot noise in ultrafast laser-induced electron emission","authors":"Y. Zhu, L. Ang","doi":"10.1109/PLASMA.2013.6634953","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6634953","url":null,"abstract":"Summary form only given. Shot noise is the fluctuation in the electrical signal due to the discreteness of electron charges1. The deviation of the uncorrelated shot noise is normally given by the Fano factor. Ultrafast electron pulse with high rightness and coherence can be generated by illumination of a dc-based metallic field emitter with femtosecond laser pulses2. A nonequilibrium model based on Boltzmann's equation has been used to explain the electron emission process3. Based on this model, the shot noise of the emission current is calculated. The effects of the shot noise reduction on applied dc voltage, laser intensity, pulse duration and metal work function are investigated. It is found that the Fano factor increases with small applied dc voltage, large laser field and longer time of tip and pulse interaction4. Our result would be helpful for investigate the coherence properties of ultrafast electron sources.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"18 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74080632","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.2013.6633428
J. Cary, R. Crockett, N. Xiang
Summary form only given. Satisfying the Courant-Friedrichs-Lewy condition when computing plasma or pure field evolution with electromagnetics is often computationally prohibitive. For example, when computing the propagation of ion-cyclotron waves in fusion plasmas, the CFL condition leads to the requirement of a time step 103 times smaller than the time scales of physical interest. We have developed a new, scalable EM solver that gets around this condition. We have shown that this solver takes roughly 10× the computational work for one step, but we have been able to use it to take time steps that are 100× greater, thus resulting in a factor of 10 in savings of computing time. Thus, the solver allows one to efficiently retain inductive effects while taking time steps much greater than that allowed by the explicit CFL condition. Verification studies and applications to low-temperature plasmas and inductive modeling will be presented.
{"title":"Implicit electromagnetic solver with plasma applications","authors":"J. Cary, R. Crockett, N. Xiang","doi":"10.1109/PLASMA.2013.6633428","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633428","url":null,"abstract":"Summary form only given. Satisfying the Courant-Friedrichs-Lewy condition when computing plasma or pure field evolution with electromagnetics is often computationally prohibitive. For example, when computing the propagation of ion-cyclotron waves in fusion plasmas, the CFL condition leads to the requirement of a time step 103 times smaller than the time scales of physical interest. We have developed a new, scalable EM solver that gets around this condition. We have shown that this solver takes roughly 10× the computational work for one step, but we have been able to use it to take time steps that are 100× greater, thus resulting in a factor of 10 in savings of computing time. Thus, the solver allows one to efficiently retain inductive effects while taking time steps much greater than that allowed by the explicit CFL condition. Verification studies and applications to low-temperature plasmas and inductive modeling will be presented.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"48 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79120964","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.2013.6633255
C. Tenholt, O. Kester, P. Spiller, U. Blell
For the transfer of ions between synchrotrons or for the final focus on targets, pulsed iron free quadrupole lenses are well suited. For those applications an extremely high field gradient is needed, that cannot be achieved with standard magnets as they are limited by saturation of the iron yoke. Another option would be superconducting magnets. High current pulsed lenses are able to produce a similar gradient for a short time as the superconducting magnets without the complex cryogenic systems. At least one doublet is needed to focus the ion bunches in both x- and y-axes. The current needed to reach magnetic field gradients for typical beam energies of the SIS18 is about 400 kA. Therefore the pulse duration need to be a few 10 μsec long. It is achieved by discharging a capacitor bank through a spark gap. The pulse is then applied to the four conductors forming the quardupole, which are switched in series. Each conductor is built of many separate lead strands, which are drilled and isolated against each other. By this the impacts of the skin effect are compensated. The shape of the conductor equals a cos(2θ)-distribution with respect to their dimensions and the distance to the beam. For the protection of close-by beamline components the quadrupole is shielded by an electromagnetic barrier which is laminated to avoid eddy currents. The concept and simulations will be presented.
{"title":"PPPS-2013: High current iron-free pulsed quadrupole lenses","authors":"C. Tenholt, O. Kester, P. Spiller, U. Blell","doi":"10.1109/PLASMA.2013.6633255","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633255","url":null,"abstract":"For the transfer of ions between synchrotrons or for the final focus on targets, pulsed iron free quadrupole lenses are well suited. For those applications an extremely high field gradient is needed, that cannot be achieved with standard magnets as they are limited by saturation of the iron yoke. Another option would be superconducting magnets. High current pulsed lenses are able to produce a similar gradient for a short time as the superconducting magnets without the complex cryogenic systems. At least one doublet is needed to focus the ion bunches in both x- and y-axes. The current needed to reach magnetic field gradients for typical beam energies of the SIS18 is about 400 kA. Therefore the pulse duration need to be a few 10 μsec long. It is achieved by discharging a capacitor bank through a spark gap. The pulse is then applied to the four conductors forming the quardupole, which are switched in series. Each conductor is built of many separate lead strands, which are drilled and isolated against each other. By this the impacts of the skin effect are compensated. The shape of the conductor equals a cos(2θ)-distribution with respect to their dimensions and the distance to the beam. For the protection of close-by beamline components the quadrupole is shielded by an electromagnetic barrier which is laminated to avoid eddy currents. The concept and simulations will be presented.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"289 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85243336","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.2013.6633472
E. Oks
Summary form only given. This paper presents a review of recent development of physical and performances of co called “fore-vacuum plasma electron sources” operated at pressure range 10-100 Pa. A number of unique parameters of the e-beam were obtained, such as electron dc energy (to 20 keV), dc beam current (up 0.5 A), pulsed current (up to 100A, 1 ms) and total e-beam power (up to 5 kW). For electron beam generation at these relatively high pressures, the following special features are important: high probability of electrical breakdown within the accelerating gap, a strong influence of back-streaming ions both the emission electrode and the emitting plasma, generation of secondary plasma in the beam propagation region, and intense beam-plasma interactions that lead in turn to broadening of the beam energy spectrum and beam defocusing. The descriptions of several fore-pump plasma electron sources, its performances and parameters are also presented. Main application area is electron beam treatment of non-conducting high temperature ceramics.
{"title":"Recent development of the fore-vacuum plasma electron sources","authors":"E. Oks","doi":"10.1109/PLASMA.2013.6633472","DOIUrl":"https://doi.org/10.1109/PLASMA.2013.6633472","url":null,"abstract":"Summary form only given. This paper presents a review of recent development of physical and performances of co called “fore-vacuum plasma electron sources” operated at pressure range 10-100 Pa. A number of unique parameters of the e-beam were obtained, such as electron dc energy (to 20 keV), dc beam current (up 0.5 A), pulsed current (up to 100A, 1 ms) and total e-beam power (up to 5 kW). For electron beam generation at these relatively high pressures, the following special features are important: high probability of electrical breakdown within the accelerating gap, a strong influence of back-streaming ions both the emission electrode and the emitting plasma, generation of secondary plasma in the beam propagation region, and intense beam-plasma interactions that lead in turn to broadening of the beam energy spectrum and beam defocusing. The descriptions of several fore-pump plasma electron sources, its performances and parameters are also presented. Main application area is electron beam treatment of non-conducting high temperature ceramics.","PeriodicalId":6313,"journal":{"name":"2013 Abstracts IEEE International Conference on Plasma Science (ICOPS)","volume":"75 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79491574","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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