Results 171 to 180 of about 260,823 (197)
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Positron diffusion in Mo: The role of epithermal positrons
Physical Review B, 1987Positrons at keV energies, incident on Mo(111) are observed to escape the sample prior to thermalization. Analysis of positron back-diffusion data shows that an excess contribution of ``hot'' positronium (Ps) seriously affects positron mobility measurements. Suppressing the ``hot'' Ps fraction the positron diffusion coefficient is shown to vary as ${T}^
P. Hautojärvi +3 more
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Positron profiles and positron annihilation in thin layers
physica status solidi (a), 1982The moderated positron density distribution over the sample depth is properly calculated. The results obtained are used as the basis for the positron annihilation probability in thin foils and surface layers. The annihilation photon angular distribution (APAD) for the double-layer samples is measured.
A. D. Pogrernyak +2 more
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The International Journal of Applied Radiation and Isotopes, 1960
Abstract Short-lived Ga68 can be prepared from its long-lived parent, Ge68, thus providing a convenient source of positron-emitting activity for medical or other applications. Solvent extraction is used for the rapid separation of the gallium daughter and a method for the production of the germanium parent is given.
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Abstract Short-lived Ga68 can be prepared from its long-lived parent, Ge68, thus providing a convenient source of positron-emitting activity for medical or other applications. Solvent extraction is used for the rapid separation of the gallium daughter and a method for the production of the germanium parent is given.
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Ophthalmology, 2012
We report the correlation of the neuro-ophthalmological findings with a 18 F-fluorodeoxyglucose positron emission tomography-computed tomography study ( 18 F-FDG-PET/ CT) in a pediatric patient affected by a pure right homon- ymous hemianopia manifested after minor head injury and no evidence of any lesions at other neuroimage studies, visual evoked ...
Cistaro, Angelina +9 more
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We report the correlation of the neuro-ophthalmological findings with a 18 F-fluorodeoxyglucose positron emission tomography-computed tomography study ( 18 F-FDG-PET/ CT) in a pediatric patient affected by a pure right homon- ymous hemianopia manifested after minor head injury and no evidence of any lesions at other neuroimage studies, visual evoked ...
Cistaro, Angelina +9 more
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Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2004
Abstract Study of positrons in the Universe is one of the major subjects of high-energy astrophysics, insofar as positrons are known to be copiously produced in a large diversity of cosmic sites. High-energy positrons are generated in the decay from particles produced in nuclear interactions of cosmic-ray protons and nuclei with interstellar atoms ...
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Abstract Study of positrons in the Universe is one of the major subjects of high-energy astrophysics, insofar as positrons are known to be copiously produced in a large diversity of cosmic sites. High-energy positrons are generated in the decay from particles produced in nuclear interactions of cosmic-ray protons and nuclei with interstellar atoms ...
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Radiation Physics and Chemistry (1977), 1984
One of the most exciting new techniques introduced in the last ten years is positron emission tomography (PET). PET provides quantitative, three-dimensional images for the study of specific biochemical and physiological processes in the human body.
Mirko Diksic +4 more
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One of the most exciting new techniques introduced in the last ten years is positron emission tomography (PET). PET provides quantitative, three-dimensional images for the study of specific biochemical and physiological processes in the human body.
Mirko Diksic +4 more
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Positrons in benzenediols [PDF]
Journal of Radioanalytical and Nuclear Chemistry Articles, 1996 Temperature dependence of positronium formation probabilityP was measured for catechol, resorcinol and hydroquinone. The variations ofP with temperature and relative permittivity can be explained in the framework of spur reaction mode. It seems that the spur processes are important at the first stage of Ps formation, the final value ofP depends also on
Jan Wawryszczuk +3 more
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Positron Polarons and Positron Trapping by Defects in LiF
Journal of the Physical Society of Japan, 1975The momentum distribution of annihilation photon pairs in LiF observed at 293 K was found to be slightly broader than that at 89 K. Assuming that the positrons are thermalized and annihilate mainly in the polaron states, the broadening was analyzed in terms of their effective mass.
Osamu Sueoka +3 more
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Positron trapping model including spatial diffusion of the positron
Physical Review B, 1985The trapping model for the annihilation rate of positrons implanted in solids has been combined with a diffusion model for the spatial motion of the implanted positrons prior to annihilation. Results are given for a simple system having traps only at the surface of a sample and allowing no detrapping, and for a general case where both effects are ...
Kelvin G. Lynn +2 more
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Positron-reemission-microscope study of positron implantation and diffusion
Physical Review B, 1991The results of high-resolution laterally resolved measurements of positron implantation and diffusion are presented. High-magnification (4400\ifmmode\times\else\texttimes\fi{}), transmission-mode positron-reemission-microscopic images of a compound sample, which inhibited positron implantation in a well-defined region, were taken for positron ...
K. F. Canter, Brandes Gr, Allen P. Mills
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