Measurement of the energy and angular distribution of electrons
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Date
1979-02-05
Authors
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Journal ISSN
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Publisher
The Australian Insitute of Nuclear Science and Engineering
Abstract
Knowledge of the energy and angular distributions of electrons ejected in collisions between fast particles (10-100 keV), particularly protons, is of great importance in understanding of the damaging effects of neutrons in biological matters. For this reason the AAEC has a program to extend the knowledge of these electron distributions to the atoms and molecules which constitute living cells. Clearly there are a large number of measurements involved in such a project, the ejection, angle, ejection energy, incident ion species and energy and the target atom all being variables. For this reason our aim was to design an apparatus which would permit rapid accumulation of data. Our design is based on the 30° electrostatic analyser, in which the charged particles originating from an object point travel in a filed free region from some distance before entering a plane electrostatic field at 30° to the field boundary. The particles are focused, to second order, along a line situated outside the field region, symmetrically placed with respect to the object point. The principle if the "fountain" spectrometer has been applied to this analyser, resulting in a device which accepts particles from a point source through a small annular gap into an electrostatic field region. In applying this analyser to measurements of ejected electrons, a proton beam is fired through one point of the input annular slit. The protons, with, with energies mostly are least 100 times that of the electrons they produce, are deflected only to a negligible extent and pass out of the analyser through a small hole in the back electrostatic plate. Electrons originating from collisions at the object point enter the analyser at all points around the annual input slit, each point corresponding to a different eject angle, varying between 0 and 120°. Cannelton detectors placed around the output focal circle simultaneously measure electrons at one energy and variety of angles. Varying the electrostatic field permits the energy to be scanned. A number of measurements have been made with this apparatus.
Description
Physical copy held by ANSTO at DDC: 530.44/11
Keywords
Energy, Angular distribution, Electrons, Collisions, Particles, Atoms, Molecules, Beams, Ion beams
Citation
Gibson, D. K., & Petersen, M. C. E. (1979). Measurement of the energy and angular distribution of electrons. Paper presented to the 12th AINSE Plasma Physics Conference, 5th & 6th February, 1979 - Lucas Heights, 7th February, 1979 - University of Sydney. In 12th AINSE Plasma Physics Conference, 5th & 6th February 1979 - Lucas Heights, 7th February, 1979 - University of Sydney, Abstracts of papers, papers 1-66, (pp. 49).