Pub Date : 2006-05-14DOI: 10.1109/MODSYM.2006.365249
F. Fukawa, S. Ezawa, Y. Satoh, N. Shimomura
Ozone has many applications in various fields with an advantage of low environmental load, e.g., sterilization, deodorization and bleaching. A part of industrial applications of ozone has already been put into practical use. While the barrier discharge is mainly used for commercial production of ozone, the various discharge methods have been studied to achieve higher yield and higher concentration. A nanosecond pulsed power generator has been developed and the ozone production experiment is conducted. As the width of pulsed power shortens, the efficiency of production improves, but the load matching becomes difficult. Then, the parallel connection of reactors is adopted. The discharge volume increases with parallel reactors. The reactor is coaxial and consists of wire and cylinder electrodes. Since arc discharges are controlled due to using nanosecond pulsed power discharge on the parallel reactors, the improved shape of insulators prevents surface discharges. The 8 parallel and 12 parallel reactors give ozone yield of about 280 g/kWh for system efficiency (500 mm reactor). In this study, the improvement of load matching is important with the discharge volume for high yield
{"title":"Consideration of Reactor Configuration of High Yield Ozonizer by Nanosecond Pulsed Power Discharge","authors":"F. Fukawa, S. Ezawa, Y. Satoh, N. Shimomura","doi":"10.1109/MODSYM.2006.365249","DOIUrl":"https://doi.org/10.1109/MODSYM.2006.365249","url":null,"abstract":"Ozone has many applications in various fields with an advantage of low environmental load, e.g., sterilization, deodorization and bleaching. A part of industrial applications of ozone has already been put into practical use. While the barrier discharge is mainly used for commercial production of ozone, the various discharge methods have been studied to achieve higher yield and higher concentration. A nanosecond pulsed power generator has been developed and the ozone production experiment is conducted. As the width of pulsed power shortens, the efficiency of production improves, but the load matching becomes difficult. Then, the parallel connection of reactors is adopted. The discharge volume increases with parallel reactors. The reactor is coaxial and consists of wire and cylinder electrodes. Since arc discharges are controlled due to using nanosecond pulsed power discharge on the parallel reactors, the improved shape of insulators prevents surface discharges. The 8 parallel and 12 parallel reactors give ozone yield of about 280 g/kWh for system efficiency (500 mm reactor). In this study, the improvement of load matching is important with the discharge volume for high yield","PeriodicalId":410776,"journal":{"name":"Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium","volume":"8 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130322245","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 : 2006-05-14DOI: 10.1109/MODSYM.2006.365212
A. Benwell, S. Kovaleski, J. Gahl, R. Curry, C. Yeckel, D. Swarts
A study of dielectric flashover in SF6 in a laser triggered gas switch (LTGS) is reported. Flashover occurring on the inside of the insulating barrier of the switch leading to the eventual failure of the switch was studied. The University of Missouri-terawatt test stand is testing the trigger section of a LTGS to understand and improve the flashover characteristics of these switches. A Rimfire LTGS was modified to operate with a trigger gap voltage of 938 kV. The modified switch was tested repeatedly over a range of pressures to examine the sensitivity of switch flashover to several parameters. The aspects of the switch that were tested include triple points both due to asymmetrical torque on the endplates, and due to gaps between the insulator and endplate, and the effect of slower voltage risetime. An analysis of the early findings of this study is presented
{"title":"Investigation of Dielectric Flashover in an SF6 Filled Laser Triggered Gas Switch","authors":"A. Benwell, S. Kovaleski, J. Gahl, R. Curry, C. Yeckel, D. Swarts","doi":"10.1109/MODSYM.2006.365212","DOIUrl":"https://doi.org/10.1109/MODSYM.2006.365212","url":null,"abstract":"A study of dielectric flashover in SF6 in a laser triggered gas switch (LTGS) is reported. Flashover occurring on the inside of the insulating barrier of the switch leading to the eventual failure of the switch was studied. The University of Missouri-terawatt test stand is testing the trigger section of a LTGS to understand and improve the flashover characteristics of these switches. A Rimfire LTGS was modified to operate with a trigger gap voltage of 938 kV. The modified switch was tested repeatedly over a range of pressures to examine the sensitivity of switch flashover to several parameters. The aspects of the switch that were tested include triple points both due to asymmetrical torque on the endplates, and due to gaps between the insulator and endplate, and the effect of slower voltage risetime. An analysis of the early findings of this study is presented","PeriodicalId":410776,"journal":{"name":"Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123319638","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 : 2006-05-14DOI: 10.1109/MODSYM.2006.365175
R. Martinez, J.D. Williams
Measurements of the enhanced electric field at breakdown for perforated flat plates fabricated from carbon-carbon composite, Poco graphite, pyrolytic graphite, and molybdenum are presented. The perforated flat plates represent electrodes used in ion sources and ion thrusters and measurements are made with and without ion beamlet extraction through the perforations. A ranking of the materials is presented of their suitability in ion source applications. The electrical breakdown characteristics of candidate materials for ion optics systems used in satellite propulsion systems are of importance for several reasons, including (1) the necessity to specify the maximum applied electric field to reduce the probability of arcing and/or frequency of arcing, (2) the need to specify the maximum tolerable charge transfer level to avoid damage to the grids that would reduce their voltage standoff capability, (3) the avoidance of incessant arcing between the grids that would result in unacceptable electromagnetic interference levels, and (4) the impact that incessant arcing would have on the power production, power processing, and power distribution system
{"title":"Electric Field Breakdown Characteristics of Molybdenum and Carbon-Based Electrodes under Conditions Where Ions are being Extracted","authors":"R. Martinez, J.D. Williams","doi":"10.1109/MODSYM.2006.365175","DOIUrl":"https://doi.org/10.1109/MODSYM.2006.365175","url":null,"abstract":"Measurements of the enhanced electric field at breakdown for perforated flat plates fabricated from carbon-carbon composite, Poco graphite, pyrolytic graphite, and molybdenum are presented. The perforated flat plates represent electrodes used in ion sources and ion thrusters and measurements are made with and without ion beamlet extraction through the perforations. A ranking of the materials is presented of their suitability in ion source applications. The electrical breakdown characteristics of candidate materials for ion optics systems used in satellite propulsion systems are of importance for several reasons, including (1) the necessity to specify the maximum applied electric field to reduce the probability of arcing and/or frequency of arcing, (2) the need to specify the maximum tolerable charge transfer level to avoid damage to the grids that would reduce their voltage standoff capability, (3) the avoidance of incessant arcing between the grids that would result in unacceptable electromagnetic interference levels, and (4) the impact that incessant arcing would have on the power production, power processing, and power distribution system","PeriodicalId":410776,"journal":{"name":"Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114807480","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 : 2006-05-14DOI: 10.1109/MODSYM.2006.365272
M. Rhodes, S. Sampayan, J. Watson, G. Caporaso
We are developing oil-switched, planar-Blumlein pulse-generators for use in high-gradient dielectric-wall accelerators (DWA). This technology is applicable to a variety of applications including both proton and electron accelerators. In our designs, simple spark-gap switches are very tightly integrated to the ends of solid-insulated planar-Blumlein pulse -forming lines. We can operate the switches with either pressurized gas or liquid (oil). By using oil as the switching medium, we have eliminated the requirement for a pressure interface around the switch. We immerse the entire assembly including the switch region in oil. In gas switches, switch-gap and pressure are the free parameters to set the operating voltage. With oil switches, the adjustment parameters are gap and charging time. We have built a single-stage prototype with Mylar/oil insulation that generates a 5-ns pulse with<1-ns risetime. To date, we have achieved an operating gradient of 38 MV/m with a goal of 50 MV/m into a matched load using 50 ns pulse-charge time. We operate the switch in self-break mode. For multi-stage versions, we plan on adding triggers to the switches. We present our experimental design and most recent results
{"title":"Oil-Switched Planar Blumlein Pulse Generators for Dielectric Wall Accelerators","authors":"M. Rhodes, S. Sampayan, J. Watson, G. Caporaso","doi":"10.1109/MODSYM.2006.365272","DOIUrl":"https://doi.org/10.1109/MODSYM.2006.365272","url":null,"abstract":"We are developing oil-switched, planar-Blumlein pulse-generators for use in high-gradient dielectric-wall accelerators (DWA). This technology is applicable to a variety of applications including both proton and electron accelerators. In our designs, simple spark-gap switches are very tightly integrated to the ends of solid-insulated planar-Blumlein pulse -forming lines. We can operate the switches with either pressurized gas or liquid (oil). By using oil as the switching medium, we have eliminated the requirement for a pressure interface around the switch. We immerse the entire assembly including the switch region in oil. In gas switches, switch-gap and pressure are the free parameters to set the operating voltage. With oil switches, the adjustment parameters are gap and charging time. We have built a single-stage prototype with Mylar/oil insulation that generates a 5-ns pulse with<1-ns risetime. To date, we have achieved an operating gradient of 38 MV/m with a goal of 50 MV/m into a matched load using 50 ns pulse-charge time. We operate the switch in self-break mode. For multi-stage versions, we plan on adding triggers to the switches. We present our experimental design and most recent results","PeriodicalId":410776,"journal":{"name":"Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126285936","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 : 2006-05-14DOI: 10.1109/MODSYM.2006.365243
Y. Minamitani, Y. Ohe, Y. Higashiyama
Nanosecond and subnanosecond high voltage pulses can provide new applications. A cancer treatment by ultra-short pulse high electric field is one of them. High power pulsed microwave has been proposed to apply the high electric field for that treatment. This work focuses on the design of a compact high power pulsed microwave generator using nanosecond pulse power generator for the cancer treatment. To obtain fast rise time of voltage and current for nanosecond pulse, a switch has to have low inductance. A water gap switch has this property. As water has a dielectric strength exceeding 1 MV/cm, gap distances for switching can be reduced to several hundreds of micrometers, and still allow switching of tens of kV. The small gaps allow us to reduce the switch inductance. In this study, the water gap switch was built in a Blumlein pulse forming line. The Blumlein line was designed an impedance of 16 Omega for matching to an antenna and to provide 1 ns pulse. By using the water gap switch in the Blumlein line, the voltage rise time was obtained approximately 750 ps at 13 kV of peak pulse voltage. Electromagnetic wave was radiated in water by a loop antenna. A measuring antenna at 0.15 m and 0.4 m from the radiating antenna caught, respectively, electric field intensities of 116 kV/m and 32 kV/m. A frequency element of 250 MHz had highest intensity
{"title":"Nanosecond High Voltage Pulse Generator using Water Gap Switch for Compact High Power Pulsed Microwave Generator","authors":"Y. Minamitani, Y. Ohe, Y. Higashiyama","doi":"10.1109/MODSYM.2006.365243","DOIUrl":"https://doi.org/10.1109/MODSYM.2006.365243","url":null,"abstract":"Nanosecond and subnanosecond high voltage pulses can provide new applications. A cancer treatment by ultra-short pulse high electric field is one of them. High power pulsed microwave has been proposed to apply the high electric field for that treatment. This work focuses on the design of a compact high power pulsed microwave generator using nanosecond pulse power generator for the cancer treatment. To obtain fast rise time of voltage and current for nanosecond pulse, a switch has to have low inductance. A water gap switch has this property. As water has a dielectric strength exceeding 1 MV/cm, gap distances for switching can be reduced to several hundreds of micrometers, and still allow switching of tens of kV. The small gaps allow us to reduce the switch inductance. In this study, the water gap switch was built in a Blumlein pulse forming line. The Blumlein line was designed an impedance of 16 Omega for matching to an antenna and to provide 1 ns pulse. By using the water gap switch in the Blumlein line, the voltage rise time was obtained approximately 750 ps at 13 kV of peak pulse voltage. Electromagnetic wave was radiated in water by a loop antenna. A measuring antenna at 0.15 m and 0.4 m from the radiating antenna caught, respectively, electric field intensities of 116 kV/m and 32 kV/m. A frequency element of 250 MHz had highest intensity","PeriodicalId":410776,"journal":{"name":"Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128138337","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 : 2006-05-14DOI: 10.1109/MODSYM.2006.365245
I. Timoshkin, R. Fouracre, M. Given, S. Macgregor
lf water is stressed with a voltage pulse having a rise time of tens of nanoseconds which creates a sufficiently high electric field, streamers develop and a highly conductive channel forms between the electrodes. The intense Joule heating of the plasma in the channel results in the collapse of its electrical resistance from a few Ohms to a few tens of milliOhms with the behavior of the collapse depending on the parameters of the discharge circuit. The rapid decrease of the resistance occurs during the first quarter of the current oscillation in the circuit. During this time, the pressure inside the channel rises to several GPa, causing the channel to expand in water with a velocity of 100 to 1000 m/s driving a high power ultrasound pulse. In the present paper, a phenomenological model is discussed which describes the dynamics of the resistance of underwater spark discharges during its initial stage and allows the pressure in the acoustic pulse to be obtained. The model is based on the plasma channel energy balance equation used by Braginskii and links the hydrodynamic characteristics of the channel and the parameters of the electric driving circuit. The dynamics of the transient cavity during the dissipation of the electrical energy in the plasma channel is described and the analytical results are compared with experimental measurements of the current in the electrical circuit and the acoustic pulse profiles radiated by the transient cavities
{"title":"Analysis of the Transient Process in Underwater Spark Discharges","authors":"I. Timoshkin, R. Fouracre, M. Given, S. Macgregor","doi":"10.1109/MODSYM.2006.365245","DOIUrl":"https://doi.org/10.1109/MODSYM.2006.365245","url":null,"abstract":"lf water is stressed with a voltage pulse having a rise time of tens of nanoseconds which creates a sufficiently high electric field, streamers develop and a highly conductive channel forms between the electrodes. The intense Joule heating of the plasma in the channel results in the collapse of its electrical resistance from a few Ohms to a few tens of milliOhms with the behavior of the collapse depending on the parameters of the discharge circuit. The rapid decrease of the resistance occurs during the first quarter of the current oscillation in the circuit. During this time, the pressure inside the channel rises to several GPa, causing the channel to expand in water with a velocity of 100 to 1000 m/s driving a high power ultrasound pulse. In the present paper, a phenomenological model is discussed which describes the dynamics of the resistance of underwater spark discharges during its initial stage and allows the pressure in the acoustic pulse to be obtained. The model is based on the plasma channel energy balance equation used by Braginskii and links the hydrodynamic characteristics of the channel and the parameters of the electric driving circuit. The dynamics of the transient cavity during the dissipation of the electrical energy in the plasma channel is described and the analytical results are compared with experimental measurements of the current in the electrical circuit and the acoustic pulse profiles radiated by the transient cavities","PeriodicalId":410776,"journal":{"name":"Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128193151","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 : 2006-05-14DOI: 10.1109/MODSYM.2006.365199
J. O'Loughlin
Magnetic core pulse transformers operating in a repetitive mode must maintain the core flux density within the saturation bounds of the magnetic material to provide satisfactory performance. The instantaneous flux is established by the time integration of the induced winding voltage. Alternatively, the flux is also determined by the net instantaneous magneto-motive force acting on the core in relation to the core dimensions and material hysteresis characteristics. Core material is typically non-linear and is awkward to model, so the preferred method of flux determination is via the induced voltage integration method. During the output pulse duration, this induced voltage is forced on the core via the winding by the pulsed power source and establishes the instantaneous flux and flux time derivative during the pulse. In the steady state, the integration of the induced voltage that occurs between load pulses, commonly called the back-swing period, must equal the value established by the output or load portion of the pulse to avoid saturation. This back-swing period can be driven by an external forced re-set source or by the stored energy in the transformer acting through the equivalent circuit impedance. In this paper only the stored energy re-set process is analyzed
{"title":"Reset Behavior of High Duty Cycle Pulse Transformers","authors":"J. O'Loughlin","doi":"10.1109/MODSYM.2006.365199","DOIUrl":"https://doi.org/10.1109/MODSYM.2006.365199","url":null,"abstract":"Magnetic core pulse transformers operating in a repetitive mode must maintain the core flux density within the saturation bounds of the magnetic material to provide satisfactory performance. The instantaneous flux is established by the time integration of the induced winding voltage. Alternatively, the flux is also determined by the net instantaneous magneto-motive force acting on the core in relation to the core dimensions and material hysteresis characteristics. Core material is typically non-linear and is awkward to model, so the preferred method of flux determination is via the induced voltage integration method. During the output pulse duration, this induced voltage is forced on the core via the winding by the pulsed power source and establishes the instantaneous flux and flux time derivative during the pulse. In the steady state, the integration of the induced voltage that occurs between load pulses, commonly called the back-swing period, must equal the value established by the output or load portion of the pulse to avoid saturation. This back-swing period can be driven by an external forced re-set source or by the stored energy in the transformer acting through the equivalent circuit impedance. In this paper only the stored energy re-set process is analyzed","PeriodicalId":410776,"journal":{"name":"Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium","volume":"14 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131224670","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 : 2006-05-14DOI: 10.1109/MODSYM.2006.365223
T. Tang, A. Kuthi, F. Wang, M. Gundersen
Here we present the design and implementation of a magnetic reactor driven diode opening switch (DOS) pulse generator, which is capable of delivering 20ns wide, 60 kV amplitude pulses into a 200 Omega load at a repetition rate of 1 kHz. The pulse generator is also capable of working without a diode stage to generate 100 ns 30 kV pulses into the same load. The generator consists of 3 isolated units with distinct functions. The first is an IGBT switched LC resonator, which generates a 2.3 mus wide 18 kV amplitude pulse into the next stage. The second unit is a 2-stage magnetic reactor using a saturable inductor wound on low-loss nanocrystalline core, which compresses the pulse width to 200 ns with the same amplitude. The compressed pulse can be directly delivered to a 200 Omega load through a 1:2 transformer and generate 100 ns wide 30 kV amplitude pulses. The output of the magnetic compression stage can also be fed into a diode output stage through the same saturable transformer for further compression. The DOS output unit utilizes 6 series connected VMI fast recovery diodes as opening switch to commute 300 A current into the load and produces 60kV 20ns pulses. The all-solid-state design helps to get reproducible pulses and reliable, long-life operation
{"title":"Design of 60kV, 2Ons Solid-state Pulse Generator Based on Magnetic Reactor Driven Diode Opening Switch","authors":"T. Tang, A. Kuthi, F. Wang, M. Gundersen","doi":"10.1109/MODSYM.2006.365223","DOIUrl":"https://doi.org/10.1109/MODSYM.2006.365223","url":null,"abstract":"Here we present the design and implementation of a magnetic reactor driven diode opening switch (DOS) pulse generator, which is capable of delivering 20ns wide, 60 kV amplitude pulses into a 200 Omega load at a repetition rate of 1 kHz. The pulse generator is also capable of working without a diode stage to generate 100 ns 30 kV pulses into the same load. The generator consists of 3 isolated units with distinct functions. The first is an IGBT switched LC resonator, which generates a 2.3 mus wide 18 kV amplitude pulse into the next stage. The second unit is a 2-stage magnetic reactor using a saturable inductor wound on low-loss nanocrystalline core, which compresses the pulse width to 200 ns with the same amplitude. The compressed pulse can be directly delivered to a 200 Omega load through a 1:2 transformer and generate 100 ns wide 30 kV amplitude pulses. The output of the magnetic compression stage can also be fed into a diode output stage through the same saturable transformer for further compression. The DOS output unit utilizes 6 series connected VMI fast recovery diodes as opening switch to commute 300 A current into the load and produces 60kV 20ns pulses. The all-solid-state design helps to get reproducible pulses and reliable, long-life operation","PeriodicalId":410776,"journal":{"name":"Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130947456","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 : 2006-05-14DOI: 10.1109/MODSYM.2006.365294
R. Campbell, B. Crichton, R. Fouracre, I. Timoshkin, M. Given
The application of pulsed electric fields (PEF) to biological cells induces trans-membrane potentials that can give rise to significant biological effects, predominantly electroporation. Recently, the effects of sub-microsecond intense electrical pulses (sm-PEF) on cellular organelles have been reported. In such applications, instantaneous power is high (~MW) but, due to the short pulse duration, energy delivered to cells and tissues is low (~nJ per cell). Electroporation is used mainly for transfections of exogenous materials, but many other interventions are possible, including microbial deactivation, whereas sm-PEF has shown particular promise in medical fields, including oncology. In this paper, the response of cells to PEF and sm-PEF is examined using an equivalent circuit model (ECM) where a network of electrical components is used to represent the cell and its environment. The model is validated through comparison with independent analytical and numerical studies. It is shown that the ECM, which is not computationally demanding, may be usefully adopted to examine how a cell and organelle respond to a wide range of cell parameters and pulse types. It is considered that such mathematical models, which can help to establish a quantitative link between the application of a time-varying electromagnetic pulse and the subsequent cell response, may allow the possible correlation between such responses and microbiological measurements to be investigated. It is anticipated that the development of these modeling approaches will aid in the analysis of those experimental measurements that are presently considered to be unattainable through real stochastic studies
{"title":"Evaluation of Induced Voltage on Biological Cell Membranes","authors":"R. Campbell, B. Crichton, R. Fouracre, I. Timoshkin, M. Given","doi":"10.1109/MODSYM.2006.365294","DOIUrl":"https://doi.org/10.1109/MODSYM.2006.365294","url":null,"abstract":"The application of pulsed electric fields (PEF) to biological cells induces trans-membrane potentials that can give rise to significant biological effects, predominantly electroporation. Recently, the effects of sub-microsecond intense electrical pulses (sm-PEF) on cellular organelles have been reported. In such applications, instantaneous power is high (~MW) but, due to the short pulse duration, energy delivered to cells and tissues is low (~nJ per cell). Electroporation is used mainly for transfections of exogenous materials, but many other interventions are possible, including microbial deactivation, whereas sm-PEF has shown particular promise in medical fields, including oncology. In this paper, the response of cells to PEF and sm-PEF is examined using an equivalent circuit model (ECM) where a network of electrical components is used to represent the cell and its environment. The model is validated through comparison with independent analytical and numerical studies. It is shown that the ECM, which is not computationally demanding, may be usefully adopted to examine how a cell and organelle respond to a wide range of cell parameters and pulse types. It is considered that such mathematical models, which can help to establish a quantitative link between the application of a time-varying electromagnetic pulse and the subsequent cell response, may allow the possible correlation between such responses and microbiological measurements to be investigated. It is anticipated that the development of these modeling approaches will aid in the analysis of those experimental measurements that are presently considered to be unattainable through real stochastic studies","PeriodicalId":410776,"journal":{"name":"Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133662605","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 : 2006-05-14DOI: 10.1109/MODSYM.2006.365279
K. Frank, I. Petzenhauser, U. Blell
The design of the pulse forming network (PFN) for the injection/extraction kicker magnet system of the future heavy ion synchrotron accelerator complex SIS100/300 at the Gesellschaft fuer Schwerionenforschung (GSI) requires an high-voltage switch, that can handle an hold-off voltage up to 70 kV, peak currents up to 6 kA and pulse durations up to 7 mus. It is planned to use instead of commercially available high-voltage thyratrons multigap pseudospark switches. In this paper the reported experimental data have been obtained by using a prototype two-gap pseudospark switch with hold-off voltages up to 30 kV. The long-term goal of the development is to construct a multigap pseudospark switch, which can handle the specifications listed before. The emphasis of the actual experiments is directed to the problems correlated with the triggering of such a multigap systems. Two trigger methods have been studied, the so-called high-dielectric trigger (HDT), which already has proven its long term capability, and a novel system, based upon the electron emission of carbon nanotubes (CNT), which is actually more of principle interest. It still suffers from an insufficient small lifetime of 104 discharges. For both trigger units and for the first gap the measured delay and jitter vary from 50 to 60 ns and 15 to 30 ns, respectively. For the second gap delay and jitter increase up to 200 and 45 ns, respectively
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