Twenty-First International Power Modulator Symposium, Conference最新文献

{"title":"High Gain GaAs Switches For Impulse Sources; Measurement Of The Speed Of Current Filaments","authors":"G. Loubriel, F. Zutavern, M. O’Malley, R. R. Gallegos, W. Helgeson, H. Hjalmarson, A. Baca, T. A. Plut","doi":"10.1109/MODSYM.1994.597058","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597058","url":null,"abstract":"A high peak power impulse pulser that is controlled with high gain, optically triggered GaAs Photoconductive Semiconductor Switches (PCSS) has been constructed and tested. The system has a short 50 ohm line that is charged to 100 kV and discharged through the switch when the switch is triggered with as little as 90 nJ of laser energy. The authors have demonstrated that the GaAs switches can be used to produce either a monocycle or a monopulse with a period of total duration of about 3 ns. For the monopulse, the voltage switched was above 100 kV, producing a peak power of about 48 MW to the 30 ohm load at a burst repetition rate of 1 kHz. The laser that is used is a small laser diode array whose output is delivered through a fiber to the switch. The current in the system has rise times of 430 ps and a pulse width of 1.4 ns when two laser diode arrays are used to trigger the switch. The small trigger energy and switch jitter are due to a high gain switching mechanism in GaAs. This experiment also shows a relationship between the rise time of the voltage across the switchmore » and the required trigger energy and switch jitter. The time evolution of the current filaments in an optically triggered, high gain GaAs switch was studied by recording the infrared photoluminescence from the filaments. When the system is triggered with two laser diode arrays that are activated within 1 ns of each other, two current filaments are observed. By delaying one laser with respect to the other, the evolution of the filament was recorded in a time resolved fashion. The filament that is triggered first crosses the switch, the voltage drops and the other filament ceases to grow. By varying the delay between the trigger lasers, the tip velocity is measured to be up to 5.9 {+-} 1 {times} 10{sup 9} cm/s.« less","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"48 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":"134569116","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}

{"title":"Reliability Upgrade Of The Harwell 136 Mev Electron Linear-accelerator Modulators","authors":"L. Kettle, H. Menown, B. Newton, P.J. Cracknell","doi":"10.1109/MODSYM.1994.597059","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597059","url":null,"abstract":"","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"1 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":"131113552","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}

{"title":"Investigation Of Triangular Aperture Grid For Plasma Switch Devices","authors":"I. Djachiachvili, M. El-Genk","doi":"10.1109/MODSYM.1994.597092","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597092","url":null,"abstract":"","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"57 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":"128406282","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}

{"title":"Crossatron Modulator Designs And Performance For Plasma-based Ion Implantation Systems","authors":"D. Goebel, W. Reass","doi":"10.1109/MODSYM.1994.597029","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597029","url":null,"abstract":"electrons produced by ion bombardment of the cathode surface are Plasma Ion Implantation (HI) is a proven process to improve trapped in a CUSP magnetic field localized near the cathode, and the surface characteristics of a broad spectrum of manufacturing travel in cycloidal ExB orbits around the cylindrical anode due to and tooling products. Tooling such as punches, drills and dies the radial electric field in the switch and the axial component of the have all shown significant lifetime improvements. In the PI1 magnetic field prior to being collected by the anode or grids. The process, the object to be implanted is placed in a weakly ionized long path length of the electrons near the cathode surface enhances plasma and pulsed to a high negative voltage. Ions in the plasma ionization of the hydrogen background gas, and reduces the are accelerated through the sheath at the plasma boundary into the pressure and plasma density (compared to thyratrons) at which the material, changing the surface chemical and physical composition. switch operates so that grid controlled interruption is possible. PI1 requires high voltage (2100 kV), high average-power The switch is closed by pulsing the control grid positive (>>lo kW) modulators to process relatively large-size parts in a relative to the cathode to initiate the plasma, and then allowing the reasonable amount of time. The load impedance of the PI1 pulse plasma to diffuse into the anode gap. Interruption of the plasma modulator is highly variable, and can change over an order of current is achieved by pulsing the control grid negative with magnitude during the 10-to-20 psec pulse period. The modulator respect to cathode potential. The flow of plasma from the must also accept different impedances due to changes in the PI1 production region near the cathode through the grid apertures is system which occur during process development and optimization. then blocked by the formation of a growing Child-Langmuir sheath A flexible and efficient modulator system for PI1 should have a in the apertures that eventually electrostatically closes the hole. switching device that is capable of providing the high current-surge The switch opens as the plasma erodes from the gap between the characteristic of the beginning of the pulse with low series control grid and the anode. The maximum interruptible current is switching losses, and provide some manner of fault protection determined by the plasma density in the control-grid apertures during target arcing. The CROSSATRON switch is a device well required to conduct the peak-current, the diameter of the apertures, suited to this requirements. A 100-kV CROSSATRON modulator and the bias applied to the grid. If fault currents in the switch built for the PI1 program and operated at Hughes has provided exceed a critical level, for example, they cannot be interrupted hard-tube-like modulation at voltages of over 100 kV, peak because the overly-dense plasma in the control grid regio","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"150 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":"132990092","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}

{"title":"Experiments Involving A Spiral Generator Used As A Transient High Voltage Generator","authors":"P. Pelletier, J. O'Loughlin, S. Calico, M. Scott, D. Voss","doi":"10.1109/MODSYM.1994.597085","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597085","url":null,"abstract":"","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"14 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":"133270806","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}

{"title":"High Voltage Thyristor Switch For Pulse Power Applications","authors":"E. Spahn, G. Buderer, E. Ramezani","doi":"10.1109/MODSYM.1994.597051","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597051","url":null,"abstract":"Investigations were made to replace spark gaps by thyristors as main switches for electromagnetic launching applications. Experiments with different kinds of thyristors showed that reverse blocking thyristors with optimized turn-on capability are ideal candidates for pulse power applications. They have an interdigitated gate structure, which enables a high current rate (> 700 A/ps), and a sufficient current capability (Imax = 90 kA). Since the blocking voltage of the used device is limited to 3.0 kV several thyristors have to be put in series to apply the switch at the operating voltage of 10 kV. In order to avoid a serial configuration of thyristors a 11 kV-thyristor device has been developed, by stacking thyristor chips one upon the other and surrounding the whole stack by a common housing. This device has the same current and current rate capability as an ordinary serial configuration of thyristors, whereas the volume and the inductance are strongly reduced. Due to its compactness and a newly developed gate unit with a high current rate and a dispersion less than 50 ns there is no requirement to protect the newly developed device by a snubber circuit (saturable reactors, freewheel diode, etc.). The compact thyristor stack was applied as main switch to a 50 kJ-capacitor. Together with a diode crowbar switch, also based on multichip technology, and an inductance, a pulse forming unit for electromagnetic launching applications has been built and tested successfully.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"34 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":"130547871","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}

{"title":"Modular Transmitter Design For The AN/FPS-85 Phased-array Radar","authors":"M. Grimes, J. M. Major, T. Warnagiris","doi":"10.1109/MODSYM.1994.597071","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597071","url":null,"abstract":"The AN/FPS-85 is a large fixed-position phased-array radar located east of Eglin AFB in Florida (see Figure 1). The radar consists of separate transmit and receive arrays located in adjoining wedge-shaped buildings facing south toward the Gulf of Mexico. A matrix of separate transmit modules arranged in a 72-row by 72column matrix make up the transmit array for a total of 5,184 transmit elements. The radar transmit beam is steered electronically by phase differentials between adjoining rows and column beam steering signals. Each transmit module is rated for a maximum RF output of 10 kW peak at a maximum duty cycle of 0.005. \"Graceful degradation\" of performance of the vacuum tubes over time reduces the transmitter output to a mean peak power of about 5-6 kW for a total radar output peak power of about 32 MW'. Design Description: Original Design","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"1 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":"125874853","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}

{"title":"A New Approach To Series Semiconductor Switch Applications","authors":"H. Tromp, P. Swart, D. Mulder, J. J. Nel, H. V. von Bergmann","doi":"10.1109/MODSYM.1994.597048","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597048","url":null,"abstract":"Previous reports showed that series semiconductor stacks could outperform thyratrons in ccrtain laser applications'. The arduous requirements of ensuring voltage sharing in series-connected high-voltage semiconductor configurations, does however limit the implementation of this technique. A new approach to solving this problem is the series stacking of multiple LC inversion stages, operating at voltages that can be withheld by single scmiconductor elcmcnts. Each stage consists of a series pair of capacitors, a thyristor with optically isolated gate drive circuitry and isolated charging transformer windings with associated diode networks. The current and voltage ratings requircd of the thyristors and diodes in each of the stages can be adapted to fall well within the capabilities of commercial devices. The peak current requirements of the thyristors, laid down by the pulse width and pulse energy, can be accommodated, as the switching of large peak currents at short pulse widths by mcans of thyristors has bccti demonstrated in lhe litcraturc2. A single stage syslcm, charging 1 J at 2 kV, with a pulse width of 1.5 pS and a peak current of 2.5 kA has been constructed and tcstcd. An overall energy eficiency of 80% has been achicvcd. Experimental results are presented.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"22 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":"127544744","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}

{"title":"Flexible Repetitive Pulser For Low-temperature Pasteurization Of Foods","authors":"H. Hammon, S. Hitchcock, D. Spelts, R. Shaw","doi":"10.1109/MODSYM.1994.597030","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597030","url":null,"abstract":"Physics International has developed an extremely flexible repetitive pulser, the RP 1292, which allows widely adjustable operating voltage, repetition rate, pulse duration, and pulse energy. The pulser, recently delivered and installed at Washington State University. was developed for use in research into the use of pulse electric fields for the pasteurization of foods at low temperature. A photograph of the interior of the pulser cabinet is shown in Figure 1. Features of the pulser include:","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"68 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":"127583703","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}

{"title":"A Long Pulse Modulator For Reduced Size And Cost","authors":"H. Pfeffer, L. Bartelson, K. Bourkland, C. Jensen, Q. Kerns, P. Prieto, G. Saewert, D. Wolff","doi":"10.1109/MODSYM.1994.597039","DOIUrl":"https://doi.org/10.1109/MODSYM.1994.597039","url":null,"abstract":"A novel modulator has been designed, built and tested for the TESLA test facility. This e{sup +} e{sup {minus}} accelerator concept uses superconducting RF cavities and requires 2ms of RF power at 10 pps. As the final accelerator will require several hundred modulators, a cost effective, space saving and high efficiency design is desired. This modulator used a modest size switched capacitor bank that droops approximately 20% during the pulse. This large droop is compensated for by the use of a resonant LC circuit. The capacitor bank is connected to the high side of a pulse transformer primary using a series GTO switch. The resonant circuit is connected to the low side of the pulse transformer primary. The output pulse is flat to within 1% for 1.9 ms during a 2.3 ms base pulse width. Measured efficiency, from breaker to klystron and including energy lost in the rise time, is approximately 85%.","PeriodicalId":330796,"journal":{"name":"Twenty-First International Power Modulator Symposium, Conference","volume":"131 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":"122491234","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}