We demonstrated that EDS measurement can be significantly improved by precessing the electron beam, thereby reducing electron channeling effects. For a SrTiO3 specimen orientated along the [001] zone axis, the measured strontium to titanium atomic ratio was 0.74-0.80 using conventional EDS methods, and the ratio was improved to ~0.99 by precessing the electron beam for angles greater than 22.54...

Here we present time-resolved in situ transmission electron microscopy (TEM) observations and real-time manipulation of nematic ordered cellulose and ultradrawn polyethylene films. Drawn films of these two polymers exhibited a unique response to the low-dose electron beam. Electron beam damage was minimal based on retention of an organized electron diffraction pattern. Increased electron dosage...

Experiments were conducted in a previously described crossed electron/molecular beam instrument1. In brief, an electron beam (~110 meV resolution) is generated with a trochoidal electron monochromator and crossed with an effusive beam of HFeCo3(CO)12 supplied through a capillary tube by sublimation at 348-353 K. The electron energy is scanned by ramping the acceleration voltage of the monochrom...

An important limit for energy gain in laser-plasma wakefield accelerators is the dephasing length, after which the electron beam reaches the decelerating region of the wakefield and starts to decelerate. Here, we propose to manipulate the phase of the electron beam in the wakefield, in order to bring the beam back into the accelerating region, hence increasing the final beam energy. This rephas...

Controlling the longitudinal distribution in an electron beam traveling through an accelerator can enhance system performance in various ways. Prebunching an electron beam in an accelerator can lead to enhanced radiation production from various emitters. Smoothing the shape of the electron beam pulse may suppress instabilities that result in beam breakup. This work, a collaboration between the ...

The BEAM code is used to simulate nine photon beams from three major manufacturers of medical linear accelerators (Varian, Elekta, and Siemens), to derive and evaluate estimates for the parameters of the electron beam incident on the target, and to study the effects of some mechanical parameters like target width, primary collimator opening, flattening filter material and density. The mean ener...

The electron beam-plasma system is ubiquitous in the space plasma environment. Here, using a Darwin particle-in-cell method, the excitation of electrostatic and whistler instabilities by a gyrating electron beam is studied in support of recent laboratory experiments. It is assumed that the total plasma frequency (xpe) is larger than the electron cyclotron frequency (Xe). The fast-growing electr...

The low emittance and short pulse electron beam is expected to be used in a wide field, such as X-ray generation by inverse Compton scattering, pulse radiolysis, etc. The laser driven photo cathode rf gun system is possible to produce the low emittance and short pulse electron beam [1]. It is very important for generating the low emittance and short pulse electron beam to measure the beam chara...

In the 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 collision at the collider ring. A new electron cooling process simulation program has been developed to fulfill the requirements of the JLEIC electro...

introduction: this study was carried out to investigate calcific tissue formation against mineral trioxide aggregate (mta) after pulp capping. materials and methods: the pulps of six teeth from four dogs were exposed and capped with mta. after extraction each tooth was sectioned into halves. each half was then further sectioned in the mesiodistal or buccolingual direction. calcified tissue of t...