Yosef Pinhasi

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An experimental project aimed at demonstrating Free Electron Maser (FEM) operation with prebunching is under way at Tel-Aviv university. The FEM utilizes a 1.0 A prebunched electron beam obtained from a microwave tube. The electron beam is bunched at 4.87 GHz and is subsequently accelerated to 70 keV. The bunched beam is injected into a planar wiggler (B, =(More)
OBJECTIVE To evaluate the relationship between the presence of microorganisms at the time of cesarean at different sites of the genital tract and the development of postpartum endometritus. METHODS One-hundred thirty-three healthy women who delivered by cesarean were enrolled in this prospective study. Cultures were obtained during the surgery and on days(More)
the exploitation of Extremely High Frequency (EHF) bands (30-300 GHz) for broadband transmission over satellite links is a hot research topic nowadays. In particular, the Q-V band (30-50 GHz) and W-band (75-110 GHz) seem to offer very promising perspectives. This paper aims at presenting an overview of the current status of research and technology in EHF(More)
The growing demand for broad-band wireless communication links and the lack of wide frequency bands within the conventional spectrum, causes us to seek bandwidth in the higher microwave and millimeter-wave spectrum at extremely high frequencies (EHF) above 30 GHz. One of the principal challenges in realizing modern wireless communication links in the EHF(More)
The wide band at extremely high frequencies (EHF) above 30 GHz is applicable for high resolution directive radars, resolving the lack of free frequency bands within the lower part of the electromagnetic spectrum. Utilization of ultra-wideband signals in this EHF band is of interest, since it covers a relatively large spectrum, which is free of users,(More)
A unified formulation of spontaneous (shot-noise) and super-radiant emissions in electron devices is presented. We consider an electron beam with an arbitrary temporal current modulation propagating through the interaction region of the electronic device. The total electromagnetic field is presented as a stochastic process and expanded in terms of(More)
The design and measurements of a resonator operating near 100 GHz and intended for use in a tandem FEL are presented. The designed resonator employs two parallel curved plates as a waveguide. In FEL operation the TE,, mode is excited. The resonator employs two wave splitters as reflectors. The wave splitters are segments of an overmoded rectangular(More)
1098-4402= We report experimental studies of the spectral linewidth and chirp characteristics of the mm-wave rf radiation of the Israeli Electrostatic-Accelerator free electron laser (EA-FEL), along with theory and numerical simulations. The simulations, matching the experimental data, were carried out using a spacefrequency-domain model. EA-FELs have the(More)
Design of a multi-stage depressed collector for efficient operation of a Free Electron Laser (FEL) oscillator requires knowledge of the electron beam energy distribution. This knowledge is necessary to determine the voltages of the depressed collector electrodes that optimize the collection efficiency and overall energy conversion efficiency of the FEL. The(More)
It is well known that electrons passing through a magnetic undulator emit partially coherent radiation: `Undulator Synchrotron Radiationa. Radiation from electrons, entering the undulator at random, adds incoherently. If the electron beam is periodically modulated (bunched) to pulses shorter than the radiation wavelength, electrons radiate in phase with(More)