نتایج جستجو برای: electron beam

تعداد نتایج: 401340  

2017
Zhen Zhang Yingchao Du Chuanxiang Tang Yuantao Ding Zhirong Huang

A novel method using high-power laser as a circular deflector is proposed for the measurement of femtosecond (fs) and sub-fs electron beam. In the scheme, the electron beam interacts with a laser pulse operating in a radially polarized doughnut mode (TEM01 ) in a helical undulator, generating angular kicks along the beam in two directions at the same time. The phase difference between the two a...

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...

2005
J. Wei W. Fischer H. C. Hseuh U. Iriso T. Roser L. Wang S. Y. Zhang

Electron cloud is one of the leading mechanisms that limit the performance of high intensity circular accelerators and colliders. In the Relativistic Heavy Ion Collider, multibunch electron cloud effects are observed both in the warm region and super-conducting region when the number of ion bunches and their intensities are raised beyond the design values. Vacuum-pressure rises, transverse tune...

Introduction: In radiation therapy, knowing the dose rates to healthy organs and tumors is beneficial, and thermoluminescent dosimeter (TLD) allows for this possibility. This study was aimed at determining the dose-response differences of TLDs in various types of radiation, energy levels, and dose rate calibrated with other types of radiation beams and energy and dose levels. Materials and Meth...

2018
H. Zhang Y. Roblin Y. Zhang Ya. Derbenev S. Benson L. Luo

In the Jefferson Lab (JLab) Electron Ion Collider (JLEIC) project the traditional electron cooling technique is used to reduce the ion beam emittance at the booster ring, and to compensate the intrabeam scattering effect and maintain the ion beam emittance during the collision at the collider ring. Different with other electron coolers using DC electron beam, the proposed electron cooler at the...

2001
S. J. Gilbert Daniel H. E. Dubin R. G. Greaves C. M. Surko

Using a new technique to generate cold electron beams, an electron-beam positron-plasma experiment was performed in a previously unexplored range of energies. An electron beam, formed from a thermalized room-temperature electron plasma, is transmitted through a positron plasma stored in a quadrupole Penning trap geometry. The transit-time instability, which is excited by the beam, was previousl...

2000
R. Brinkmann Y. Derbenev

We present a method to generate a flat (large horizontal to vertical emittance ratio) electron beam suitable for Linear Colliders. The concept is based on a round-beam rf-laser gun with finite solenoid field at the cathode together with a special beam optics adapter. Computer simulations of this new type of beam source show that the beam quality required for a Linear Collider may be obtainable ...

2013
Florian Vollnhals Tom Woolcot Marie-Madeleine Walz Steffen Seiler Hans-Peter Steinrück Geoff Thornton Hubertus Marbach

Electron beam-induced surface activation (EBISA) has been used to grow wires of iron on rutile TiO2(110)-(1 × 1) in ultrahigh vacuum. The wires have a width down to ∼20 nm and hence have potential utility as interconnects on this dielectric substrate. Wire formation was achieved using an electron beam from a scanning electron microscope to activate the surface, which was subsequently exposed to...

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