Lifetime measurements with a scanning positron microscope.
First lifetime results obtained with a scanning positron microscope will be presented. A pulsed positron beam with a variable energy from 0.5 to 20 keV, with a spot diameter of 2 microm, can be electronically scanned over an area of 0.6x0.6 mm(2). This beam is formed after a double-stage stochastic cooling (moderation) of positrons emitted from a radioactive isotope. Included in the system is a conventional scanning electron microprobe for surface analysis. Three-dimensional positron lifetime spectra of a GaAs sample with a small surface scratch reveal the range due to the mechanical damage.
David
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Institut für Nukleare Festkörperphysik, Universität der Bundeswehr München, 85577 Neubiberg, Germany.
Kögel
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Sperr
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Triftshäuser
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