Characterization of electron beams for modulated electron beam radiotherapy

The parameters of self-generated electron beams have been measured and correlated to the dynamics of a 60 kV, 28 kJ plasma focus. The electron beam emission occurs in two periods: the first corresponds to the initial formation and disruption of the pinched plasma and terminates with the disruption of the plasma column, and the second period occurs after the breaking up of the focus plasma. The first period is characterized by high-energy electron beams, whereas in the second period the electron beams have lower average energies but higher currents. A relativistic electron beam is found to occur around the time of first compression, when the plasma is observed to be macroscopically stable, in contrast to measurements obtained from machines with similar energies but operating at lower voltages. The plasma X-ray emission is observed to be closely related to the electron beam characteristics. Possible mechanisms for the formation of the electron beams observed are discussed.

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Materials for Electron Beam Information Storage

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100062671 ◽

1969 ◽

Vol 27 ◽

pp. 152-153 ◽

Cited By ~ 1

Author(s):

D. E. Speliotis

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

Recent Literature ◽

Electron Beams ◽

Information Storage ◽

The Subject ◽

The Magnetic Field

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.

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Energy Distribution in Electron Beams

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096096 ◽

1972 ◽

Vol 30 ◽

pp. 568-569

Author(s):

Tamotsu Ohno

Keyword(s):

Electron Beam ◽

Energy Distribution ◽

Cross Section ◽

Integral Curve ◽

Electron Beams ◽

Electron Gun ◽

Angular Divergence ◽

Apparent Increase ◽

Integral Width ◽

The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

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A very rapid in situ Kikuchi technique to determine relative crystal misorientation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106211 ◽

1988 ◽

Vol 46 ◽

pp. 830-831

Author(s):

J. I. Bennetch

Keyword(s):

Electron Beam ◽

Analytical Techniques ◽

Superplastic Forming ◽

The Other ◽

Kikuchi Pattern ◽

Kikuchi Line ◽

Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

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