Pub Date : 2008-07-02DOI: 10.1109/IVELEC.2008.4556551
Ming-Chieh Lin, R. Jao
Ab initio calculations are used to study the reduction of the work functions of tungsten (W) surfaces with one monolayer of adsorbed barium (Ba) and lithium atoms. We have carefully and systematically test the convergence of density-functional-theory (DFT) calculations in the local-density approximation or generalized-gradient approximation with a plane-wave basis set and ultra-soft pseudopotentials or the projector-augmented wave method as implemented in Vienna ab-initio simulation package. The DFT calculation shows that the work function of the Ba adsorbed onto a p(2times2) W(001) substrate is dramatically lowered by about 2.2 eV, provided that the fourfold hollow sites are occupied. With this approach, one can investigate more complex adsorbates onto the cathode surface of different materials.
{"title":"Dramatic lowering of work function for the barium atoms adsorbed onto a p(2x2) W(001) substrate based on Ab initio calculations","authors":"Ming-Chieh Lin, R. Jao","doi":"10.1109/IVELEC.2008.4556551","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556551","url":null,"abstract":"Ab initio calculations are used to study the reduction of the work functions of tungsten (W) surfaces with one monolayer of adsorbed barium (Ba) and lithium atoms. We have carefully and systematically test the convergence of density-functional-theory (DFT) calculations in the local-density approximation or generalized-gradient approximation with a plane-wave basis set and ultra-soft pseudopotentials or the projector-augmented wave method as implemented in Vienna ab-initio simulation package. The DFT calculation shows that the work function of the Ba adsorbed onto a p(2times2) W(001) substrate is dramatically lowered by about 2.2 eV, provided that the fourfold hollow sites are occupied. With this approach, one can investigate more complex adsorbates onto the cathode surface of different materials.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131841548","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 : 2008-07-02DOI: 10.1109/IVELEC.2008.4556391
D. Niemann, J. Silan, J. Killian, B. Ribaya, M. Rahman, C. Nguyen
In this paper we outline a process for the integration of gated CPAs. The process employed to fabricate this gated cathode is highly scaleable and promises the realization of stable high current cold cathodes with low turn-on voltages for many potential applications. In addition, we will present data detailing the field emission performance and reliability of gated carbon nanotube pillar arrays.
{"title":"Gated carbon nanotube pillar arrays for high current applications","authors":"D. Niemann, J. Silan, J. Killian, B. Ribaya, M. Rahman, C. Nguyen","doi":"10.1109/IVELEC.2008.4556391","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556391","url":null,"abstract":"In this paper we outline a process for the integration of gated CPAs. The process employed to fabricate this gated cathode is highly scaleable and promises the realization of stable high current cold cathodes with low turn-on voltages for many potential applications. In addition, we will present data detailing the field emission performance and reliability of gated carbon nanotube pillar arrays.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127446858","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 : 2008-05-01DOI: 10.1109/IVELEC.2008.4556500
Stanislav Kolosov, Alexander Kurayev
The design and the efficiency of a gyrotons-amplifiers, a gyroton-frequency multipliers and a gyroton-oscillators on corrugated resonator are presented.
介绍了波纹谐振器上的陀螺放大器、陀螺倍频器和陀螺振荡器的设计及其效率。
{"title":"Gyrotons: Amplifiers, frequency multipliers, oscillators","authors":"Stanislav Kolosov, Alexander Kurayev","doi":"10.1109/IVELEC.2008.4556500","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556500","url":null,"abstract":"The design and the efficiency of a gyrotons-amplifiers, a gyroton-frequency multipliers and a gyroton-oscillators on corrugated resonator are presented.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115525950","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 : 2008-05-01DOI: 10.1109/IVELEC.2008.4556369
V. Katsap, R. Kendall, K. Saito
In shaped-beam mask writing tools, beam current is fairly small, often under 1 muA, with required stability of Lt1%. Beam is originated at the cathode, and passes thru multitude of electron-optical components before reaching target plane. Hence, beam current stability is affected by multiple factors, like power supplies, spurious electromagnetic fields, temperature, pressure, and the emitterpsilas own instability. We report results of analysis which allows us to uncover and separate environment-related beam current instabilities from emitter-related ones.
{"title":"Beam current instability analysis with FFT","authors":"V. Katsap, R. Kendall, K. Saito","doi":"10.1109/IVELEC.2008.4556369","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556369","url":null,"abstract":"In shaped-beam mask writing tools, beam current is fairly small, often under 1 muA, with required stability of Lt1%. Beam is originated at the cathode, and passes thru multitude of electron-optical components before reaching target plane. Hence, beam current stability is affected by multiple factors, like power supplies, spurious electromagnetic fields, temperature, pressure, and the emitterpsilas own instability. We report results of analysis which allows us to uncover and separate environment-related beam current instabilities from emitter-related ones.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122468972","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 : 2008-05-01DOI: 10.1109/IVELEC.2008.4556357
A. S. Kotov, E. Gelvich, A. D. Zakurdayev, E. V. Zhary
Microwave device parameters determining the possibility of amplifying nanosecond microwave pulses and pulses with frequency and phase modulation have been defined. An example of the developed CMD able to amplify nanosecond and LFM-modulated pulses without distortions is given. Detailed theories and experiments are presented in the report.
{"title":"Research and determination of microwave amplifiers performance parameters providing unperturbed amplification of complicated and ns microwave pulses","authors":"A. S. Kotov, E. Gelvich, A. D. Zakurdayev, E. V. Zhary","doi":"10.1109/IVELEC.2008.4556357","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556357","url":null,"abstract":"Microwave device parameters determining the possibility of amplifying nanosecond microwave pulses and pulses with frequency and phase modulation have been defined. An example of the developed CMD able to amplify nanosecond and LFM-modulated pulses without distortions is given. Detailed theories and experiments are presented in the report.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114568976","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 : 2008-05-01DOI: 10.1109/IVELEC.2008.4556455
P. Ferguson, D. Whittick, S. Humphries
We present data showing the differences in modulation of the solid beam klystron and the HBK. Simulation results showing bandwidth and RF output power vs. RF input power was presented.
{"title":"Development of a 10 MW- 201.25 MHz Hollow Beam Klystron","authors":"P. Ferguson, D. Whittick, S. Humphries","doi":"10.1109/IVELEC.2008.4556455","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556455","url":null,"abstract":"We present data showing the differences in modulation of the solid beam klystron and the HBK. Simulation results showing bandwidth and RF output power vs. RF input power was presented.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124850846","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 : 2008-05-01DOI: 10.1109/IVELEC.2008.4556371
L. Behnke, R. True, R. Watkins
Ceramic jacketed mini-TWT collectors are used in a number of TWT designs at L-3 EDD. In applications where size is a critical constraint, the ceramic jacketed collector is often the only option that will satisfy the power density requirement as well as the form factor requirement. Cracking of the ceramic can occur, however, typically during aging and initial testing of TWTs containing these collectors. The goal of this study is to analyze the design of the collector in order to reduce the incidence of cracking.
{"title":"Thermal mechanical study of mini-TWT ceramic jacketed collectors","authors":"L. Behnke, R. True, R. Watkins","doi":"10.1109/IVELEC.2008.4556371","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556371","url":null,"abstract":"Ceramic jacketed mini-TWT collectors are used in a number of TWT designs at L-3 EDD. In applications where size is a critical constraint, the ceramic jacketed collector is often the only option that will satisfy the power density requirement as well as the form factor requirement. Cracking of the ceramic can occur, however, typically during aging and initial testing of TWTs containing these collectors. The goal of this study is to analyze the design of the collector in order to reduce the incidence of cracking.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132719596","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 : 2008-05-01DOI: 10.1109/IVELEC.2008.4556497
J. Kinross-wright, I. Roth, M. Gaudreau, M. Kempkes
In this paper, DTI will describe its recent efforts in the design of a compact, 300 kW, 1.5 ms amplifier for pulsed superconducting accelerators. Due to its unique design, the amplifier has applications to a wide range of accelerator technologies.
{"title":"The single cavity amplifier — An optimized RF power source for pulsed superconducting accelerators","authors":"J. Kinross-wright, I. Roth, M. Gaudreau, M. Kempkes","doi":"10.1109/IVELEC.2008.4556497","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556497","url":null,"abstract":"In this paper, DTI will describe its recent efforts in the design of a compact, 300 kW, 1.5 ms amplifier for pulsed superconducting accelerators. Due to its unique design, the amplifier has applications to a wide range of accelerator technologies.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127155647","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 : 2008-05-01DOI: 10.1109/IVELEC.2008.4556538
V. Perevodchikov, P. Stalkov, V. Shapenko
Static VAR compensators (SVC) have been developed and introduced in the power industry and such equipment improves the quality of electrical transmission systems due to regulation of active and reactive power. Devices known as FACTS (Flexible AC Transmission Systems) operate at voltages of 35 kV, 110 kV and above. At such high voltage levels, the use of vacuum switch devices becomes competitive with semiconductor devices. The fact is that vacuum devices provide high voltage levels (100 kV and above), in comparison with semiconductor devices (6-7 kV). For use in high-voltage converters consecutive connection of many semiconductor devices with control circuitry is necessary. There are also other advantages of vacuum devices: high speed switching, stability of influence of electromagnetic interferences and heating. High-voltage breakdown in vacuum devices does not carry catastrophic character, unlike breakdown in semiconductor devices.
{"title":"Electrons deceleration on the anode and prospects of powerful switch tubes for converting technics","authors":"V. Perevodchikov, P. Stalkov, V. Shapenko","doi":"10.1109/IVELEC.2008.4556538","DOIUrl":"https://doi.org/10.1109/IVELEC.2008.4556538","url":null,"abstract":"Static VAR compensators (SVC) have been developed and introduced in the power industry and such equipment improves the quality of electrical transmission systems due to regulation of active and reactive power. Devices known as FACTS (Flexible AC Transmission Systems) operate at voltages of 35 kV, 110 kV and above. At such high voltage levels, the use of vacuum switch devices becomes competitive with semiconductor devices. The fact is that vacuum devices provide high voltage levels (100 kV and above), in comparison with semiconductor devices (6-7 kV). For use in high-voltage converters consecutive connection of many semiconductor devices with control circuitry is necessary. There are also other advantages of vacuum devices: high speed switching, stability of influence of electromagnetic interferences and heating. High-voltage breakdown in vacuum devices does not carry catastrophic character, unlike breakdown in semiconductor devices.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134064793","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 : 2008-05-01DOI: 10.1109/ivelec.2008.4556502
A. A. Kurayev, A. K. Sinitsyn
It is shown, that in coaxial gyroklinotron the averages all over the wide electron beam (EB) efficiency reaches to 55% at optimized inclination angle of ring resonator about the axis of design and tubular EB. The design of coaxial gyroklinotron-klystron and gyroklinotron-TWT had been proposed.
{"title":"Coaxial gyroklinotrons","authors":"A. A. Kurayev, A. K. Sinitsyn","doi":"10.1109/ivelec.2008.4556502","DOIUrl":"https://doi.org/10.1109/ivelec.2008.4556502","url":null,"abstract":"It is shown, that in coaxial gyroklinotron the averages all over the wide electron beam (EB) efficiency reaches to 55% at optimized inclination angle of ring resonator about the axis of design and tubular EB. The design of coaxial gyroklinotron-klystron and gyroklinotron-TWT had been proposed.","PeriodicalId":113971,"journal":{"name":"2008 IEEE International Vacuum Electronics Conference","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126336300","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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