نتایج جستجو برای: electron beams

تعداد نتایج: 336996  

2001
M. Takanaka

Characteristics of electron-cooled bunched ion beams have been studied using the particle-tracking simulation in which the space-charge force and the force induced through the transverse broadband impedance are taken into account. The beams become space-charge dominated during the bunching of coasting beams. The simulation results show that the beams meet the transverse instability which can be...

2000
W. Mondelaers P. Cauwels B. Masschaele M. Dierick J. Jolie S. Baechler T. Materna

In an increasing range of research fields there is a strong demand of high-intensity tunable monochromatic X-ray sources. A promising new approach for the production of tunable high-intensity monochromatic beams in the hard X-ray region is the use of electron accelerators of moderate energy (10 MeV range). We developed at the 15 MeV linear electron accelerator of the Ghent University a monochro...

Journal: :Physical review letters 2017
Koen van Kruining Armen G Hayrapetyan Jörg B Götte

We present a relativistic description of electron vortex beams in a homogeneous magnetic field. Including spin from the beginning reveals that spin-polarized electron vortex beams have a complicated azimuthal current structure, containing small rings of counterrotating current between rings of stronger corotating current. Contrary to many other problems in relativistic quantum mechanics, there ...

Journal: :Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology 1995
J Izewska R Gajewski B Gwiazdowska M Kania J Rostkowska

The aim of the TLD pilot study was to investigate and to reduce the uncertainties involved in the measurements of absorbed dose and to improve the consistency in dose determination in the regional radiotherapy centres in Poland. The intercomparison was organized by the SSDL. It covered absorbed dose measurements under reference conditions for Co-60, high energy X-rays and electron beams. LiF po...

2016
Ming-Hao Liu Cosimo Gorini Klaus Richter

An electron collimator composed of a point-like source and a parabolic pn junction is proposed as a generator of highly focused electron beams in graphene. The collimator is based on negative refraction and Klein collimation, which are unique to pseudo-relativistic Dirac materials. The electron beams generated by the lensing apparatus can be steered by a weak magnetic field without losing colli...

2002
Sol M. Gruner Don Bilderback Ivan Bazarov Ken Finkelstein Lia Merminga Thomas Jefferson Hasan Padamsee Qun Shen Charles Sinclair Maury Tigner

Practically all synchrotron x-ray sources to data are based on the use of storage rings to produce the high current electron ~or positron! beams needed for synchrotron radiation ~SR!. The ultimate limitations on the quality of the electron beam, which are directly reflected in many of the most important characteristics of the SR beams, arise from the physics of equilibrium processes fundamental...

2003
A. Murokh

The electric field intensity of the compressed ultrarelativistic electron beams is approaching GV/m levels, which is sufficient to cause observable tunneling effect in the low band gap materials. In this article the tunneling ionization rate is estimated for the experimentally available electron beam parameters, and a proposed proof of principle experiment is outlined. Tunneling effect has expo...

2014
Giulio Guzzinati Laura Clark Armand Béché Jo Verbeeck

The recent demonstration of electron vortex beams has opened up the new possibility of studying orbital angular momentum (OAM) in the interaction between electron beams and matter. To this aim, methods to analyze the OAM of an electron beam are fundamentally important and a necessary next step. We demonstrate the measurement of electron beam OAM through a variety of techniques. The use of forke...

2008
E. W. Schmidt D. Bernhardt J. Hoffmann M. Lestinsky D. V. Lukić A. Müller D. A. Orlov D. W. Savin S. Schippers

The rate coefficient for dielectronic recombination (DR) of Ne-like Fe forming Na-like Fe was measured employing the merged electron-ion beams technique at the heavyion storage-ring TSR of the Max-Planck-Institut für Kernphysik in Heidelberg, Germany. In the electron-ion collision energy range of 240–840 eV the merged-beams recombination rate coefficient is dominated by DR associated with 2s 2p...

Introduction: The use of electrons in the electron therapy to destroy tumoral tissue is dedicated significant contribution of different methods of radiation therapy. Scattered radiation due to exited electrons of the applicator affect the dose out of the field in the patient's normal tissue. The aim of this study is to determine the peripheral dose outside the applicator in the...

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