Pub Date : 1994-06-27DOI: 10.1109/MODSYM.1994.597097
L. Ducimetière, P. Faure, U. Jansson, H. Riege, K. Schmidt, G. Schroder, E. Vossenberg, J. Hańderek, P. Bénin, L. Courtois
The kicker magnet pulse generators for the beam dumping system of CERNs Large Hadron Collider (LHC) require fast high power switches (35 kV, 30 kA, 8 ps) of very low repetition rate (only a few pulses per day). Cold cathode tubes like pseudo-spark switches look suitable for this kind of application, as they do not suffer from cathode-heater lifetime limitations and may guarantee a quasi unlimited operation time. Pseudo-spark assemblies are therefore under development with the aim of obtaining a switch tailored to two main requirements of the LHC dumping system, a very low prefire rate (-10-4) and a large ratio of maximum to minimum operation voltage (-15). It is intended to achieve these goals with a 2-gap or 3-gap version employing a ferroelectric trigger in each of the gaps. Experimental results on several 1-gap prototypes of different electrode diameter will be reported. Two of the prototypes have been mounted in a sealed-off version, equipped with a deuterium gas reservoir. The erosion behaviour has been investigated for different electrode materials, pure tungsten, thoriated tungsten and tungstedrhenium (5% Re). Important differences in the quenching behaviour between pure and thoriated tungsten have been found. The incorporation of these results into a 2-gap beam dump switch, soon to be assembled, will be discussed.
欧洲核子研究中心(CERNs)大型强子对撞机(LHC)束流倾倒系统的触发磁体脉冲发生器需要非常低重复率(每天只有几个脉冲)的快速高功率开关(35 kV, 30 kA, 8 ps)。像伪火花开关这样的冷阴极管看起来适合这种应用，因为它们不受阴极加热器寿命限制的影响，可以保证准无限的操作时间。因此，伪火花组件正在开发中，目的是获得适合LHC倾倒系统的两个主要要求的开关，非常低的预燃率(-10-4)和最大最小工作电压(-15)的大比。它的目的是实现这些目标与一个2-间隙或3-间隙版本采用铁电触发器在每个间隙。本文将报道几种不同电极直径的单间隙原型的实验结果。其中两个原型机已经安装在一个密封的版本中，配备了一个氘气储层。研究了纯钨、钍化钨和5%稀土三种电极材料的腐蚀行为。发现了纯钨和含钍钨在淬火行为上的重要区别。将这些结果整合到即将组装的2间隙光束转储开关中，将进行讨论。
{"title":"Pseudo-spark Switch Development For The LHC Beam Dumping System","authors":"L. Ducimetière, P. Faure, U. Jansson, H. Riege, K. Schmidt, G. Schroder, E. Vossenberg, J. Hańderek, P. Bénin, L. Courtois","doi":"10.1109/MODSYM.1994.597097","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597097","url":null,"abstract":"The kicker magnet pulse generators for the beam dumping system of CERNs Large Hadron Collider (LHC) require fast high power switches (35 kV, 30 kA, 8 ps) of very low repetition rate (only a few pulses per day). Cold cathode tubes like pseudo-spark switches look suitable for this kind of application, as they do not suffer from cathode-heater lifetime limitations and may guarantee a quasi unlimited operation time. Pseudo-spark assemblies are therefore under development with the aim of obtaining a switch tailored to two main requirements of the LHC dumping system, a very low prefire rate (-10-4) and a large ratio of maximum to minimum operation voltage (-15). It is intended to achieve these goals with a 2-gap or 3-gap version employing a ferroelectric trigger in each of the gaps. Experimental results on several 1-gap prototypes of different electrode diameter will be reported. Two of the prototypes have been mounted in a sealed-off version, equipped with a deuterium gas reservoir. The erosion behaviour has been investigated for different electrode materials, pure tungsten, thoriated tungsten and tungstedrhenium (5% Re). Important differences in the quenching behaviour between pure and thoriated tungsten have been found. The incorporation of these results into a 2-gap beam dump switch, soon to be assembled, will be discussed.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115987129","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 : 1994-06-27DOI: 10.1109/MODSYM.1994.597084
B. Wernsman, M. El-Genk
An experimental determination of the modulation capabilities of different grid designs in a Cs-Ba tacitron is made as a function of operating parameters. Results show that as the modulation frequency increases, the current modulation of the device is harder to control (ignite and extinguish) due to a decrease in the ion leakage rate from the discharge volume after the device is ignited. As the transparency decreases from 34 % to 26 % for a grid with 0.5 mm apertures, the device is harder to ignite, but easier to extinguish. Lowering the transparency of the grid also increases the forward voltage drop, at a given cesium reservoir temperature, and decreases by 50 % the range of cesium reservoir temperatures at which the device modulates. However, decreasing the grid aperture size makes the device easier to extinguish without affecting ignition.
{"title":"Modulation Capabilities Of Different Grid Designs For A Cs-ba Tacitron","authors":"B. Wernsman, M. El-Genk","doi":"10.1109/MODSYM.1994.597084","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597084","url":null,"abstract":"An experimental determination of the modulation capabilities of different grid designs in a Cs-Ba tacitron is made as a function of operating parameters. Results show that as the modulation frequency increases, the current modulation of the device is harder to control (ignite and extinguish) due to a decrease in the ion leakage rate from the discharge volume after the device is ignited. As the transparency decreases from 34 % to 26 % for a grid with 0.5 mm apertures, the device is harder to ignite, but easier to extinguish. Lowering the transparency of the grid also increases the forward voltage drop, at a given cesium reservoir temperature, and decreases by 50 % the range of cesium reservoir temperatures at which the device modulates. However, decreasing the grid aperture size makes the device easier to extinguish without affecting ignition.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132314576","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 : 1994-06-27DOI: 10.1109/MODSYM.1994.597037
H. Anamkath, E. Gower, D. Palmer, K. Whitham, A. Zante
H. Anamkath, E. Gower, D. Palmer, K. Whitham, A. Zante The TITAN Corporation, TITAN Beta Division 6780 Sierra Court, Dublin, California 94568 A very high power modulator was built for TRW Space and Technology for new generation tube development. This modulator has successfblly produced the highest known combinations of peak and average power for high power microwave tube development work. The parameters of this modulator are consistent with or exceed the RF pulsed power expected to be required for the next linear collider. This paper describes the system configuration and the factory test results.
H. Anamkath, E. Gower, D. Palmer, K. Whitham, A. Zante The TITAN Corporation, TITAN Beta Division 6780 Sierra Court, Dublin, California 94568一个非常高功率的调制器是为TRW空间和技术公司建造的，用于新一代管的开发。该调制器已成功地为高功率微波管的开发工作产生了已知的最高峰值和平均功率组合。该调制器的参数符合或超过下一个线性对撞机所需的射频脉冲功率。本文介绍了系统结构和出厂测试结果。
{"title":"Very High Power 300 KW Modulator","authors":"H. Anamkath, E. Gower, D. Palmer, K. Whitham, A. Zante","doi":"10.1109/MODSYM.1994.597037","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597037","url":null,"abstract":"H. Anamkath, E. Gower, D. Palmer, K. Whitham, A. Zante The TITAN Corporation, TITAN Beta Division 6780 Sierra Court, Dublin, California 94568 A very high power modulator was built for TRW Space and Technology for new generation tube development. This modulator has successfblly produced the highest known combinations of peak and average power for high power microwave tube development work. The parameters of this modulator are consistent with or exceed the RF pulsed power expected to be required for the next linear collider. This paper describes the system configuration and the factory test results.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133196925","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 : 1994-06-27DOI: 10.1109/MODSYM.1994.597074
A. Campbell, M. Grippeling, G. Mcmonagle, P. Pearce, G. Rentier
{"title":"A Klystron-modulator Interlock And Fault Acquisition System Using G-64, VME, And MIL-1553-B Standards","authors":"A. Campbell, M. Grippeling, G. Mcmonagle, P. Pearce, G. Rentier","doi":"10.1109/MODSYM.1994.597074","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597074","url":null,"abstract":"","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115444472","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 : 1994-06-27DOI: 10.1109/MODSYM.1994.597091
I. Druckmann
It is known that the volume of core required for a magnetic pulse compressor (MPC) of given gain y is proportional to 9 and to pr,80f, the relative permeability at saturation. The latter is empirically found to be 2-5. We are interested in obtaining low values for pr,sat, in order to decrease the core volume. pr,sat is clearly related to H,, the amplitude of the magnetizing field in the core. The article investigates the dependence of H, and pr,sat on the other parameters of the MPC. It is shown that H, and depend on the gain y, and are independent of N, the number of turns. More precisely, H, is a decreasing function of y, and pr,sat an increasing one. The exact form of these functions depend on the form of the function p,. = g(H). Several functions g are investigated, including one based on measured data. The conclusion is, that the amount of core volume increases faster with y, than is predicted by the 9 factor in the classical volume formula.
已知，给定增益y的磁脉冲压缩机(MPC)所需的磁芯体积与9和饱和时的相对磁导率pr,80f成正比。后者的实证值为2-5。我们感兴趣的是获得较低的pr,sat值，以减少核心体积。pr,sat与磁心磁场振幅H明显相关。本文研究了H、pr、sat对MPC其他参数的依赖关系。结果表明，H与增益y有关，与转数N无关。更准确地说，H是y的递减函数，pr是y的递增函数。这些函数的确切形式取决于函数p的形式。= g (H)。研究了几个函数g，包括一个基于实测数据的函数g。结论是，堆芯体积随y的增加比经典体积公式中的9因子所预测的要快。
{"title":"A Theorem On The Dependence Of Hm On Gain In A Magnetic Pulse Compressor, And Its Implications On The Core Volume Formula","authors":"I. Druckmann","doi":"10.1109/MODSYM.1994.597091","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597091","url":null,"abstract":"It is known that the volume of core required for a magnetic pulse compressor (MPC) of given gain y is proportional to 9 and to pr,80f, the relative permeability at saturation. The latter is empirically found to be 2-5. We are interested in obtaining low values for pr,sat, in order to decrease the core volume. pr,sat is clearly related to H,, the amplitude of the magnetizing field in the core. The article investigates the dependence of H, and pr,sat on the other parameters of the MPC. It is shown that H, and depend on the gain y, and are independent of N, the number of turns. More precisely, H, is a decreasing function of y, and pr,sat an increasing one. The exact form of these functions depend on the form of the function p,. = g(H). Several functions g are investigated, including one based on measured data. The conclusion is, that the amount of core volume increases faster with y, than is predicted by the 9 factor in the classical volume formula.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115020427","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 : 1994-06-27DOI: 10.1109/MODSYM.1994.597076
J. Tsinetakes
One of the traditional methods for describing the transient behavior of a charged transmission line pulse generator is the bounce diagram technique, Alternatively, a Laplace transform of the pulse generator circuit can be done to yield a mathematical expression of its output. Both of these techniques can be applied to a single charged line with relatively little effort. An investigation is made into the application of these techniques to multisection lines. The results of these two analysis techniques are compared to the results obtained from circuit analysis software, such as PSpice.
{"title":"Transient Analysis Methods For Multisection Charged Transmission Line Pulse Generators","authors":"J. Tsinetakes","doi":"10.1109/MODSYM.1994.597076","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597076","url":null,"abstract":"One of the traditional methods for describing the transient behavior of a charged transmission line pulse generator is the bounce diagram technique, Alternatively, a Laplace transform of the pulse generator circuit can be done to yield a mathematical expression of its output. Both of these techniques can be applied to a single charged line with relatively little effort. An investigation is made into the application of these techniques to multisection lines. The results of these two analysis techniques are compared to the results obtained from circuit analysis software, such as PSpice.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129865158","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 : 1994-06-27DOI: 10.1109/MODSYM.1994.597050
W. Carey, W. Nunnally
{"title":"Generation Of Sub-nanosecond Pulses Using A Solid State Marx Circuit With Trapatt Diode Switches","authors":"W. Carey, W. Nunnally","doi":"10.1109/MODSYM.1994.597050","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597050","url":null,"abstract":"","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130779291","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 : 1994-06-27DOI: 10.1109/MODSYM.1994.597090
C. Nowak, J. Stopher, J. Zirnheld, R. Dollinger
Higher frequency power is playing an increasingly important role in the power conditioning and high power electronics areas. This is evident in manv new applications of high frequency devices such as sw'itching power supplies, radar modulators, and numerous pulsed power applications. Multi-factor stressing and related erosion of the dielectric material from microdischarges form a dominant cause of device failure, and this insulation deterioration can be accelerated under higher frequency stressing. The methods developed t o investigate component failure have been established in the past by 60 Hz system requirements. Conventional detection systems are designed for dc, 60 Hz, and 400 Hz, but cannot generally be applied at high frequencies. This lack of high frequency diagnostic capabilities has contributed t o a poor understanding of aging processes and failure mechanisms in new high frequency devices. To help researchers understand the fundamental aging processes and reliably be able t o predict service lifetimes, new tools that can detect and analyze microdischarge activity under high frequency conditions a re being developed. This paper describes the design of a new microdischarge detection technique that can be used at high frequencies, and it 's application t o capacitors. This technique uses a series resonant multikilohertz power system in which the primary capacitance is two capacitors under tes t . Preliminary assessment of this new detection technique have validated its applicability t o high frequency components. Initial test data and it's relevance will be discussed in detail. This new detection technique offers a multi-spectral diagnostic capability which will help advance scientific understanding of the fundamental aging processes under the high frequency conditions for which the devices are designed.
{"title":"Microdischarge Detection In High Frequency Capacitors","authors":"C. Nowak, J. Stopher, J. Zirnheld, R. Dollinger","doi":"10.1109/MODSYM.1994.597090","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597090","url":null,"abstract":"Higher frequency power is playing an increasingly important role in the power conditioning and high power electronics areas. This is evident in manv new applications of high frequency devices such as sw'itching power supplies, radar modulators, and numerous pulsed power applications. Multi-factor stressing and related erosion of the dielectric material from microdischarges form a dominant cause of device failure, and this insulation deterioration can be accelerated under higher frequency stressing. The methods developed t o investigate component failure have been established in the past by 60 Hz system requirements. Conventional detection systems are designed for dc, 60 Hz, and 400 Hz, but cannot generally be applied at high frequencies. This lack of high frequency diagnostic capabilities has contributed t o a poor understanding of aging processes and failure mechanisms in new high frequency devices. To help researchers understand the fundamental aging processes and reliably be able t o predict service lifetimes, new tools that can detect and analyze microdischarge activity under high frequency conditions a re being developed. This paper describes the design of a new microdischarge detection technique that can be used at high frequencies, and it 's application t o capacitors. This technique uses a series resonant multikilohertz power system in which the primary capacitance is two capacitors under tes t . Preliminary assessment of this new detection technique have validated its applicability t o high frequency components. Initial test data and it's relevance will be discussed in detail. This new detection technique offers a multi-spectral diagnostic capability which will help advance scientific understanding of the fundamental aging processes under the high frequency conditions for which the devices are designed.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130287965","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 : 1994-06-27DOI: 10.1109/MODSYM.1994.597089
R. Stemprok, K. Zieher
current density of 100 A/cm2 [1,31. The Plasma Edge Cathode concept can possibly produce high electron current densities while avoiding or delaying plasma closure of the extraction gap of an electron source. An obstacle partially intercepts the plasma jet emitted from a spark plug and causes a stationary transverse plasma boundary from which electrons are extracted. The plasma should experience negligible external electric forces as long as the extraction is space charge limited. It should be possible to avoid the plasma closure of the extraction gap and obtain an extracted electron current density over 100 A/cm2 for practical plasmas. Experimental results partially support this theoretical prediction. Electron current densities up to 40 A/cm2 were obtained repeatedly with a duration up to 2.5 ps. The pepper-pot method was used to measure the effective emittance of the extracted electron beam. The images (50 ns exposure time) were digitized by a scanner and a computer code determined the effective emittance. An extraction gap of 15 mm together with an extraction voltage less than 20 kV yielded a relatively smooth pattern on the scintillator. About half of the 100 shots taken so far could be clearly scanned and evaluated. They have suitable exposure and separated spots. The effective emittance E' = 4x,, xim, and = 4y,, yims are of the order of 5 ~ 1 0 ~ m r a d = 1 . 6 ~ 1 0 ~ x m r a d with some shots down to 10-3mrad = 3 . 2 ~ 1 0 ~ x m r a d . At higher extraction voltages the pattern was irregular and indicated some instability of the plasma surface. The normalized brightness was found typically in the range from 2x 1 O6 to 2x lo7 A/m2rad2.
电流密度为100 A/cm2[1,31]。等离子体边缘阴极概念可能产生高电流密度，同时避免或延迟等离子体关闭电子源的提取间隙。障碍物部分拦截从火花塞发射的等离子体射流并产生一个固定的横向等离子体边界，从中提取电子。只要萃取是空间电荷有限的，等离子体就会受到可以忽略不计的外力。对于实际的等离子体，应该可以避免等离子体闭合提取间隙，并获得超过100 A/cm2的提取电子电流密度。实验结果部分支持这一理论预测。重复获得了高达40 A/cm2的电子电流密度，持续时间高达2.5 ps。使用胡椒罐法测量了提取的电子束的有效发射度。图像(曝光时间为50ns)由扫描仪数字化，计算机编码确定有效发射度。提取间隙为15mm，提取电压小于20kv时，在闪烁体上产生了相对光滑的图案。迄今为止拍摄的100张照片中，大约有一半可以被清晰地扫描和评估。它们有合适的曝光和分开的斑点。有效发射度E′= 4x，， xim，和= 4y，， yims的数量级为5 ~ 10 ~ m r和d = 1。6 ~ 10 ~ 10 μ m / d，有的可达10 ~ 3 μ m / d。2 ~ 10 ~ x m r a d。在较高的萃取电压下，图案不规则，表明等离子体表面有一定的不稳定性。归一化亮度通常在2x 1o6到2x lo7 A/m2rad2之间。
{"title":"Emittance Measurement Of An Electron Beam Extracted From A Plasma Edge Cathode","authors":"R. Stemprok, K. Zieher","doi":"10.1109/MODSYM.1994.597089","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597089","url":null,"abstract":"current density of 100 A/cm2 [1,31. The Plasma Edge Cathode concept can possibly produce high electron current densities while avoiding or delaying plasma closure of the extraction gap of an electron source. An obstacle partially intercepts the plasma jet emitted from a spark plug and causes a stationary transverse plasma boundary from which electrons are extracted. The plasma should experience negligible external electric forces as long as the extraction is space charge limited. It should be possible to avoid the plasma closure of the extraction gap and obtain an extracted electron current density over 100 A/cm2 for practical plasmas. Experimental results partially support this theoretical prediction. Electron current densities up to 40 A/cm2 were obtained repeatedly with a duration up to 2.5 ps. The pepper-pot method was used to measure the effective emittance of the extracted electron beam. The images (50 ns exposure time) were digitized by a scanner and a computer code determined the effective emittance. An extraction gap of 15 mm together with an extraction voltage less than 20 kV yielded a relatively smooth pattern on the scintillator. About half of the 100 shots taken so far could be clearly scanned and evaluated. They have suitable exposure and separated spots. The effective emittance E' = 4x,, xim, and = 4y,, yims are of the order of 5 ~ 1 0 ~ m r a d = 1 . 6 ~ 1 0 ~ x m r a d with some shots down to 10-3mrad = 3 . 2 ~ 1 0 ~ x m r a d . At higher extraction voltages the pattern was irregular and indicated some instability of the plasma surface. The normalized brightness was found typically in the range from 2x 1 O6 to 2x lo7 A/m2rad2.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125409941","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 : 1994-06-27DOI: 10.1109/MODSYM.1994.597088
M. El-Genk, B. Wernsman, J. Luke
The capability of the Cs-Ba tacitron as an inverter has been demonstrated, and its current modulation characteristics have been investigated. The inverter was operated in two modes, the thyratron (forced commutation) mode and the tacitron (grid controlled) mode. In the thyratron mode the tacitron was shown to modulate up to 10 kHz at a forward voltage drop as low as 2 V. In the tacitron mode, modulation frequencies up to 20 kHz at voltage drops of 3-3 5 V were demonstrated. The planar tacitron was shown to modulate 5 Ncm2 at 22 kHz, at a forward voltage drop of 2.2 V. Plasma diagnostic capability using Langmuir probes was sucessfully implemented.
{"title":"Recent Advances In Cs-Ba Tacitron Technology","authors":"M. El-Genk, B. Wernsman, J. Luke","doi":"10.1109/MODSYM.1994.597088","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597088","url":null,"abstract":"The capability of the Cs-Ba tacitron as an inverter has been demonstrated, and its current modulation characteristics have been investigated. The inverter was operated in two modes, the thyratron (forced commutation) mode and the tacitron (grid controlled) mode. In the thyratron mode the tacitron was shown to modulate up to 10 kHz at a forward voltage drop as low as 2 V. In the tacitron mode, modulation frequencies up to 20 kHz at voltage drops of 3-3 5 V were demonstrated. The planar tacitron was shown to modulate 5 Ncm2 at 22 kHz, at a forward voltage drop of 2.2 V. Plasma diagnostic capability using Langmuir probes was sucessfully implemented.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126083444","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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