نتایج جستجو برای: electron field diode

تعداد نتایج: 1079656  

اخیانی, مینا, جهانگیری, فاضل, رضایی پندری, محمد, مسعودی, رضا, نیکنام, علیرضا,

In this paper, electron acceleration in the field of laser pulse is investigated. To limit the interaction region for electron pulse, which is required for acceleration, a new method is presented based on the injection of electron on temporal peak of the laser pulse. In this method, the electron is provided by a plasma source and is steered inside the laser field by utilizing the magnetic field...

Journal: :Nature Photonics 2022

Abstract Tailoring the electric-field waveform of ultrashort light pulses forms basis for controlling nonlinear optical phenomena on their genuine, attosecond timescale. Here we extend control from visible and near-infrared—where it was previously demonstrated—to mid-infrared spectral range. Our approach yields single-cycle infrared over several octaves first time. Sub-10-fs a carrier-envelope-...

1997
C. De Martinis

It is shown that non-prepoled PLZT ceramics, both in ferroelectric and antiferroelectric phase, emit intense current bursts when a negative exciting voltage is applied to the rear surface of the cathode. The spontaneous polarization induced in the bulk by applying the field through the cathode disk, creates a sheet of negative charge on the diode boundary of the ferroelectric. This, in turn, in...

1998
V. G. Anfinogentov A. E. Hramov

The paper consider a complex dynamics of electron beam with virtual cathode and local neutralization of the beam charge density near anode. Different types of nonlinear behaviour, including deterministic chaos, were treated. It is shown that chaotic dynamics arises as results of spatiotemporal structures interaction. Introduction and model In the present paper we consider a electrostatic shortc...

2016
Yujiao Qin Hualiang Zhong Ning Wen Karen Snyder Yimei Huang Indrin J. Chetty

The goal of this study was to investigate small field output factors (OFs) for flat-tening filter-free (FFF) beams on a dedicated stereotactic linear accelerator-based system. From this data, the collimator exchange effect was quantified, and detector-specific correction factors were generated. Output factors for 16 jaw-collimated small fields (from 0.5 to 2 cm) were measured using five differe...

Journal: :iranian journal of radiation research 0
m. allahverdi department of medical physics and biomedical engineering, tehran university of medical sciences, tehran, iran m. zabihzadeh department of medical physics, jondishapour university of medical sciences, ahvaz, iran m.r. ay department of medical physics and biomedical engineering, tehran university of medical sciences, tehran, iran s.r. mahdavi department of medical physics, iran university of medical sciences, tehran, iran m. shahriari department of nuclear engineering, shahid beheshti university, tehran, iran a. mesbahi department of medical physics, tabriz university of medical sciences, tabriz, iran

background: the electron contamination may reduce or even diminish the skin sparing property of the megavoltage beam. the detailed characteristics of contaminant electrons are presented for different field sizes and cases. materials and methods: the monte carlo code, mcnpx, has been used to simulate 18 mv photon beam from a varian linac-2300 accelerator. all dose measurements were carried out u...

Journal: :Medical dosimetry : official journal of the American Association of Medical Dosimetrists 2017
Juan Diego Azcona Benigno Barbés Verónica Morán Javier Burguete

This study aimed to describe the commissioning of small field size radiosurgery cones in a 6-MV flattening filter free (FFF) beam and report our measured values. Four radiosurgery cones of diameters 5, 10, 12.5, and 15 mm supplied by Elekta Medical were commissioned in a 6-MV FFF beam from an Elekta Versa linear accelerator. The extraction of a reference signal for measuring small fields in sca...

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