IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)最新文献

{"title":"Life model of coated and uncoated thermionic dispenser cathodes","authors":"A. P. Makarov","doi":"10.1109/IVESC.2004.1414136","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414136","url":null,"abstract":"The life model for uncoated and coated (with osmium, indium film or film made from their alloys with refractory metals) thermionic dispenser cathodes has been developed based on the study of physical and chemical processes taking place within the volume and on the surface of these cathodes, depending on the operating temperature and the time of the operation as well as on the film systems simulating the operation of these cathodes. The model presented here, as well as the life models of the dispenser cathodes described earlier is based on the statement that the electron emission and lifetime of the dispenser cathodes at operating temperatures largely depend on the degree of their emitting surface coating with a film consisting of co-adsorbed atoms of barium and oxygen as well as the crystallographic structure and electronic properties of a refractory substrate material and the value of barium and oxygen atom flow from the volume to the surface of the cathode.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129663090","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":"Arc-plasma deposited dispenser cathode for use in powerful flow water vacuum electron heater","authors":"V. Abrosimov, O. Maslennikov","doi":"10.1109/IVESC.2004.1414200","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414200","url":null,"abstract":"A principal new design of vacuum electron heater is presented. The vacuum electronic heater (VEH) is developed as a vacuum diode and contains a thermionic cathode and an anode. The anode is cooled by flowing water. The thermonic dispenser cathode heated by tungsten heater emits an electron current. Kinetic energy of the electrons accelerated by the supply-line voltage of the anode is transformed to the anode heat. Therefore the flow water in the jacket is heated. Smooth control of output power is provided by variation of working temperature of the dispenser cathode in range of from 700 up to 1000/spl deg/C. Cathode is located in vacuum volume on the legs and hermetically fastened in an insulator. The cathode of VEH has form of cylinder with outer diameter of 22-24mm and height of not less than 100mm. Porous tungsten matrix with thickness of 0.5-0.7mm is built on the surface of molybdenum cylinder by arc-plasma deposition method. The matrix is impregnated by emission substance with composition of 3BaO-CaO-Al/sub 2/O/sub 3/ and then the emitting surface is formed by mechanical treatment to get needed dimensions. During VEH operation current density on the cathode emission surface isn't higher than IA/cm/sup 2/.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"3 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120863601","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 gate turn-on voltages of InGaP/InGaAs camel-gate n- and p-channel pseudomorphic modulation-doped field effect transistors prepared by low-pressure MOCVD","authors":"J. Tsai, King-Poul Zhu, Ying-Cheng Chu, S. Chiu","doi":"10.1109/IVESC.2004.1414278","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414278","url":null,"abstract":"The authors demonstrate and compare the experimental results of the high-performance InGaP /InGaAs camel-gate n-channel and p-channel /spl delta/-doped pseudomorphic modulation-doped field effect transistors (pMODFETs). For the n-channel device, because of the p-n depletion in the camel-like gate region and the presence of large conduction band discontinuity at InGaP/InGaAs heterostructure, an extremely large gate turn-on voltage than 1.7 V is measured. However, the p-channel device exhibits a larger turn-on voltage than 2 V due to the relatively large valence band discontinuity at InGaP/InGaAs heterostructure.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117193136","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":"Application of integrative cathode-heater component element to TWT","authors":"Lu Wei-yuan, Zhang Jingzhi, Zhen Youlai","doi":"10.1109/IVESC.2004.1414261","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414261","url":null,"abstract":"In fact, fast start of microwave tube is that its cathode can quickly get in operation state, i.e. has shorter preheating time. It's a way to turn cathode gaining heat energy through radiation and conduction. This thesis introduced how to integrate heater with cathode together with the aid of a transition material, so preheating time reduce for the cathode of diameter less than 7mm. The thesis also introduced the basic construction of the component element, the measuring method and result of the component performance and situation of application to TWT.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134083427","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":"Development of coherent electron emission source of Pd-atom nanotips","authors":"E. Rokuta, G. Oshima","doi":"10.1109/IVESC.2004.1414139","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414139","url":null,"abstract":"We have fabricated nano-scaled Pd atom clusters to apply to a field electron source, and the electron emission characteristics were investigated. Owing to the formation of the Pd nanotips, field electron beams were drastically converged within a cone angle of approximately 5 degree. This collimation of the electron beams was quite relevant to the case of previously-studied W nanoemitters. Analysis based on Fowler-Nordheim formalism, where work function of W(111) was assumed, to be available for each specimen, predicts that the effective tip radius ranged from 150 and 200 nm for the conventional W emitter and from 20 to 30 nm for the Pd nanotip. Noticeably, the Pd nanotips were found to regenerate and to exhibit equivalent emission characteristics repeatedly. This unlimited revival function is significant for the practical use, and not possessed by the previously studied W nanotips.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"19 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133140694","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":"Analysis of the coaxial ridged disk-loaded slow-wave structures","authors":"Lingna Yue, Wengxiang Wang, Yanyu Wei, Y. Gong","doi":"10.1109/IVESC.2004.1414247","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414247","url":null,"abstract":"The coaxial-ridged disk-loaded structure which is a new disk-loaded periodic system is presented and analyzed in this paper. As an all-metal slow-wave circuit, it has properties that can be used in high power traveling-wave tubes (TWT) and relativistic TWTs. The dispersion equation of this structure is derived by means of the field-matching method and it may be reduced to the dispersion of a series of coaxial structures, such as: the ridged disk-loaded structure, the /spl Lambda/-like disk-loaded one and the disk-loaded one. The comparison of the dispersion characteristics between the structures above-mentioned is made. It is shown that the /spl Lambda/-like disk-loaded structure has the weaker dispersion compared with the ridged disk-loaded one or the disk-loaded one.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123952138","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":"Computer simulations of 100kW L-band CW broadband multi-beam klystron","authors":"Shen Bin, Ding Yaogen, A. N. Sandalov, V.E. Rodjakin, A.N. Chashurina","doi":"10.1109/IVESC.2004.1414252","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414252","url":null,"abstract":"Recent years the development and manufacture of the broadband (the bandwidth up to 10%) and super broadband (the bandwidth more than 10%) klystrons have been highly regarded. On one-beam devices experiments were carried out in the 70s (Metivier, 1971), then there were realization theoretical research of one-beam and multi-beam version of the broadband klystrons (Artjuh et al., 1979; Kanavets, et al., 1978). The realization of multi-beam broadband klystron was shown at the bandwidth up to 10% (Kanavets, et al., 1978). The experimental research of broadband and super broadband multi-beam klystrons (MBK) is carried out now in Institute of Electronics, Chinese Academy of Sciences, and theoretical research together with the M.V. Lomonosov Moscow State University. The calculations used 1.5D code klystron-MSU and 2.5D code arsenal-MSU (Sandalov et al., 2002) of the super broadband klystron are presented below.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129282573","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 recovery characteristics after ion bombardment on scandate cathode","authors":"M. Zhang, Honglai Zhang, Pukun Liu, Yutao Li","doi":"10.1109/IVESC.2004.1414171","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414171","url":null,"abstract":"The scandate cathode has excellent electron emission capability. However, applications in vacuum electron devices are limited because of nonuniform emission and weak resistance to ion bombardment. A new method has been adopted for making scandate cathode. This type of scandate cathode showed more uniform emission and fast recovery characteristics after ion bombardment comparing with conventional impregnated scandate cathode. The results of XPS analysis before and after ion bombardment are presented.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128586791","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":"Cathode unit with field emitter from carbon fiber","authors":"M. Chupina, O. Ivanov, O. Maslennikov, E. Orekhov","doi":"10.1109/IVESC.2004.1414224","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414224","url":null,"abstract":"In the beginning of 1990s, the cathode unit with the fiber field emitter for use in devices of surface searching and treatment was developed in SSPE \"Toriy\" (Afanasyev et al., 1992; Barsov et al., 2003). The cathode emitter is the carbon fiber with 7/spl mu/m diameter and with specially formed tip. The tip has the shape of a bullet with micro-pit on the top. Due to the pit geometry it makes focusing of the electron beam emitted by the fiber tip, so that beam is inside a small solid angle along axis of the device. Our calculations show that due to this effect the fiber emitter has high stability of emission, repeatability of characteristics for different samples of the cathode and higher level of electron optical brightness.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114270388","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":"Surface effects on voltage- and current-source bias phototransistors grown by low-pressure MOCVD","authors":"H.R. Chen, S. Tan, A. Lin, W.T. Chen, W. Lour","doi":"10.1109/IVESC.2004.1414233","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414233","url":null,"abstract":"We report on low-pressure MOCVD grown InGaP/GaAs heterojunction phototransistors (HPT) with and without passivated base surface. The typical structure consists of a 0.5-/spl mu/m n/sup +/-GaAs sub-collector (n/sup +/=5/spl times/10/sup 18/cm/sup -3/), a 0.6-/spl mu/m n/sup -/-GaAs collector (n/sup -/=5/spl times/10/sup 16-3/), a 0.14-/spl mu/m p/sup +/-GaAs base (p/sup +/=4/spl times/10/sup 19/cm/sup -3/), a 0.07-/spl mu/m n-InGaP emitter (n=5/spl times/10/sup 17/cm/sup -3/), and a 0.3-/spl mu/m n/sup +/-GaAs cap layer (n/sup +/=5/spl times/10/sup 18/cm/sup -3/). Both fabricated HBTs and HPTs have their emitter areas of 150/spl times/150 /spl mu/m/sup 2/ with an absorption area of 4/spl times/10 cm. Optical/electrical experiments and measurements include effects of base surface on optical responsivity, performances of HPTs with a voltage-source and current-source bias base. Following are our important results and conclusions. 1. Effects of base surface: (1) wide-gap InGaP as a base surface passivation layer is transparent to 850-nm incident light, (2) a higher responsivity is available for such a passivated base layer. The measured responsivity is 0.64/spl plusmn/0.01 (0.57/spl plusmn/0.01) A/W for passivated (nonpassivated) devices. 2. Voltage-source bias HPT: (1) both collector and reverse base currents saturate at their p-i-n photocurrents for both kinds of HPTs at a small voltage level; (2) there is no amplification of photocurrent generated with base-collector region if B-E junction is off conductive due to small voltage; (3) even if the applied voltage pushes a HBT to the high current gain level, the magnitude of amplification of photocurrent is only 3, which is much smaller than that from a HPT with a floating base. 3. Current-source bias HPT: both collector photocurrent and optical gain are increased with increasing input current for both kinds of HPTs. The measured collector photocurrents equal -32 and -48 times of their photocurrent. So, we conclude that pushing HBTs operating point to a high current level using a current source is able to enhance optical performances. The enhanced trend with input current is more obvious, indicating that passivated HPTs are more suitable for present applications in integrated optoelectronic circuits. Furthermore, a voltage-source and a current-source bias HPT-circuit model using extended Ebers-Moll configuration and related results calculated therein are presented in this work. It is found that calculated results are in good agreement with experimental data.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116198770","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}