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The sheet electron beam focused by periodic cusped magnetic (PCM) focusing structure could transport more stable than uniform magnetic field because of diocotron instability. We simulated, fabricate and test a w sheet electron beam klystron with multi-gaps extended interaction cavities. To obtain particular intensity of magnetic field, two pieces of PCM focusing structure had a short distance, and...
For the development of Electron Optics System (EOS) for Extended Interaction Amplifier (EIA) at frequency of 330GHz, the parameters of EOS are studied with a help of EGUN and Superfish. The design of EOS and permanent magnetic field for EIA has been conducted. The simulation results show that electron beam has highly pass rate, low ripple and good laminarity.
The THz folded waveguide (FWG) traveling wave amplifier (TWA) which is regarded as an important source in vacuum electronics is developed at Institute of Electronics, Chinese Academy of Science (IECAS). In this scheme, the circular electron beam is adopted, which can be gained the high current density of electron beam by the confined and immersed magnetic field. The folded waveguide high frequency...
The main objective of this work is to assess the possibility of improving the achievable image quality using synthetic aperture (SA) approach and to evaluate the performance of the modified algorithm. The modified algorithm is based on the coherent summation of back-scattered RF echo signals with weights calculated for each point and for all possible combinations of transmit-receive pairs. Weights...
The Total Focus Method (TFM) is a post-processing algorithm which uses all elements in the array to focus in both transmission and reception at every image point. The time-domain signals is captured in a process termed Full Matrix Capture (FMC). In this paper, the main objective is to research the effects of directivity function on the TFM. The TFM algorithm is based on the FMC data with weights calculated...
The Development of the 10MW L-band multi-beam klystron was started in the Institute of Electronics, Chinese Academy of Sciences (IECAS) three years ago. The electrical and structural designs for this klystron have been accomplished, in which many technical problems have been resolved. In the design of electron optical system, the uniform field multiple-lens focusing scheme was adopted, by which the...
The transport of an elliptic sheet electron beam with uniform density in uniform magnetic field is investigated by making use of a macroscopic cold-fluid model. General envelope equations and beam twisted angles are derived. In particular, the tilt of the elliptic sheet beam was numerically calculated by an example of W-band sheet beam klystron.
In this paper, the ponderomotive focusing forces are derived for a sheet electron beam in both periodic cusped magnetic and wiggler magnetic field configurations, which has a large aspect ratio, using two-time scale analytical method.
Simulations of the electron optics system and beam wave interaction system for W-band Sheet Beam Klystron (SBK) were done and a beam stick was fabricated. Under the beam voltage of 60 kV and current of 2.6 A, the beam transmission has achieved 99%. In this paper the results of both simulation and experiment are described.
In many applications, data does not take the form of traditional stored relations, but rather arrives in continuous, rapid, time-varying data streams,and data streams are potentially unbounded in size. Focusing on the problem of sampling from landmark windows over data streams, a new concept, which is called stratified sampling ratio function, is presented. Then a multistage stratified sampling algorithm...
The electron optics system for the W-band sheet beam klystron (WSBK) has been developed in IECAS recently. Using the wiggler focusing structure, with the beam aspect ratio of 25:1, beam voltage of 60 kV, and beam current of 2.6A, the transmission rate of sheet beam electron tube manufactured is more than 55% with the drift length 50mm. However, using the uniform focusing system and the optimum parameters,...
Many types of Multi-Beam Klystrons (MBKs) with frequency range from L to Ku band, power level of several hundred watts to several hundred kilo-watts, have been developed in China during last 17 years. The research work on both special technology and tubes will be described in this paper. The technical problems of the MBKs are also discussed.
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