Results 181 to 190 of about 260,823 (197)
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A positron lifetime spectrometer for a DC positron beam
Radiation Physics and Chemistry, 2003Abstract A lifetime spectrometer for use with an isotope-based DC positron beam is described. The system utilizes secondary electrons emitted from the sample and annihilation gamma rays to determine positron lifetimes. The device has been tested with porous silica films capped with a 25 nm layer of Cu.
Jun Xu, Jeremy Moxom
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Annual Review of Neuroscience, 1980
An understanding of disease processes in the human brain must ultimately be based on a knowledge of the underlying regional hemodynamic, metabolic, and biochemical changes. Although some such information is currently available from various animal models, the conflicting nature of these data often leaves many important questions unanswered and ...
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An understanding of disease processes in the human brain must ultimately be based on a knowledge of the underlying regional hemodynamic, metabolic, and biochemical changes. Although some such information is currently available from various animal models, the conflicting nature of these data often leaves many important questions unanswered and ...
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Effect of the Positron-Phonon Interaction on Positron Motion
Physical Review B, 1970We have made a calculation of the effect of the positron-phonon interaction on positron motion in simple cubic metals. We use a slightly modified jellium model to treat the positron-phonon interaction, and several approximations are introduced. Still, we feel confident that our calculations are qualitatively correct, and we conclude that phonons must ...
A. Perkins, J. P. Carbotte
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Radiation Effects, 1972
Abstract A beam of 1.2–MeV positrons was obtained by accelerating in a 1–MeV Van de Graaff positrons emitted by 58Co. Channeling in thin silicon crystals was studied by measuring as a function of incidence angle the yield of positrons scattered through a few degrees into an annular detector.
J. U. Andersen +2 more
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Abstract A beam of 1.2–MeV positrons was obtained by accelerating in a 1–MeV Van de Graaff positrons emitted by 58Co. Channeling in thin silicon crystals was studied by measuring as a function of incidence angle the yield of positrons scattered through a few degrees into an annular detector.
J. U. Andersen +2 more
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Physical Review B, 1985
Positron diffusion in Si(100) and Si(111) has been studied using a variable-energy positron beam. The positron diffusion coefficient is found to be ${D}_{+}$=2.7\ifmmode\pm\else\textpm\fi{}0.3 ${\mathrm{cm}}^{2}$/sec using a Makhov-type positron implantation profile, which is demonstrated to fit the data more reliably than the more commonly applied ...
Nielsen, B. +3 more
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Positron diffusion in Si(100) and Si(111) has been studied using a variable-energy positron beam. The positron diffusion coefficient is found to be ${D}_{+}$=2.7\ifmmode\pm\else\textpm\fi{}0.3 ${\mathrm{cm}}^{2}$/sec using a Makhov-type positron implantation profile, which is demonstrated to fit the data more reliably than the more commonly applied ...
Nielsen, B. +3 more
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The Propagators for Electrons and Positrons
1992In the following we will generalize the nonrelativistic propagator theory developed in the previous chapter to the relativistic theory of electrons and positrons. We will be guided by the picture of the nonrelativistic theory where the propagator G+(x′;x) is interpreted as the probability amplitude for a particle wave originating at the space–time ...
Joachim Reinhardt, Walter Greiner
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Physica Scripta, 1987
An overview is presented of the basic principles, the physics constrains and the practical limitations of Positron Emission Tomography. The most recent developments in PET instrumentation and the actual trends are discussed. Finally, some clinical applications are described.
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An overview is presented of the basic principles, the physics constrains and the practical limitations of Positron Emission Tomography. The most recent developments in PET instrumentation and the actual trends are discussed. Finally, some clinical applications are described.
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Nature, 2001
Beams of antimatter are providing some of the most detailed images yet of defects in semiconductors. Philip Ball reports.
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Beams of antimatter are providing some of the most detailed images yet of defects in semiconductors. Philip Ball reports.
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Simulation of positron spectra of a hybrid positron source
Journal of Instrumentation, 2020A. A. Savchenko, W. Wagner, B. Azadegan
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Philosophy and Phenomenological Research, 1964
Norwood Russell Hanson, V. F. Lenzen
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Norwood Russell Hanson, V. F. Lenzen
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