Results 181 to 190 of about 144,387 (227)

ANNIHILATION OF POSITRONS IN IONIC CRYSTALS

Soviet Physics Uspekhi, 1971
CONTENTS 1. Average lifetimes of positrons in ionic crystals 72 2. Relative counting rate of three-photon coincidences 74 3. Angular correlation of γ quanta in two-photon annihilation of positrons 74 4.
G.M. Bartenev, A.D. Tsyganov, Evgenii P. Prokop'ev, A.Z. Varisov   +3 more
openaire   +1 more source

Galactic positron annihilation radiation

AIP Conference Proceedings, 1987
Recent observations suggest that galactic line emission at 511 keV results from the superposition of contributions from a variable, compact source and an interstellar distribution of positrons resulting from the decay of radionuclei produced by thermonuclear burning supernovae.
R. RAMATY, R. E. LINGENFELTER
openaire   +1 more source

Theory of positron annihilation in superconductors

Physical Review B, 1989
A theory of positron annihilation in Cooper-pair superconductors is presented. It is assumed that the positron and electrons are not correlated. It is argued that a comparison of positron data with density-of-states measurements might be used to test the hypothesis that superconductivity in the high-temperature superconductors results from pair ...
, Barnes, , Peter
openaire   +2 more sources

Positron Annihilation Studies in Zeolites

physica status solidi (b), 1988
AbstractPositron annihilation experiments using both lifetime spectroscopy and Doppler broadening of the annihilation lineshape technique are performed for various pure zeolites and for mordenite impregnated with highly dispersed gold particles. Changes in the annihilation parameters are tentatively correlated with the properties of the samples and, in
Debowska, M., Abbe, J.C., Duplatre, G.
openaire   +2 more sources

Annihilation of positrons on organic molecules

Physical Review Letters, 1991
The lifetime of positrons confined in a Penning trap is studied in the presence of a variety of chemical species. The large observed annihilation rates of the positrons on these molecules provide evidence that positron-molecule attachment is a general phenomenon, and distinct chemical trends are identified.
, Murphy, , Surko
openaire   +2 more sources

Positron Annihilation in Amorphous Alloys

Physica Status Solidi (a), 1979
The crystallization process of the amorphous Pd0.845Si0.155, Pd0.80Si0.20, and Ni0.81P0.19 alloys is studied by positron annihilation. The following experimental facts are found. 1. In the PdSi alloy, the changes of coincidence peak counts and h-parameters with temperature are consistent with the crystallization mechanism proposed by Masumoto and ...
S. Tanigawa, K. Hinode, R. Nagai, K. Kanbe, M. Doyama, N. Shiotani   +5 more
openaire   +1 more source

On positron annihilation in zinc

Applied Physics, 1975
The purpose of this work is to understand Mogensen's and Petersen's positron annihilation curves for zinc. Mijnarends' approach is used as an auxiliary method of localizing inhomogeneities of the electronic density in momentum space, as defined in the paper.
G. Kontrym-Sznajd, H. Stachowiak
openaire   +1 more source

Positron annihilation in positronium hydrides

Physical Review A, 1986
The two-photon annihilation rate for positronium hydride is calculated with the use of extensive Hylleraas-type wave functions in which all six interparticle coordinates are used. The binding energy against dissociation into a positronium atom and a hydrogen atom is improved upon the previous best value by about 3.8%.
openaire   +2 more sources

Annihilation of Positrons in Gases

Physical Review, 1957
The angular correlation of the two-photon annihilation of positrons annihilating in gases at high pressures demonstrates the two modes of decay-(1) from a bound state, positronium, and (2) from an unbound state-in all gases tested that have low-lying energy states. The increase in the narrow component in Ar, plus suitable thermalizing gases, due to the
Milton Heinberg, Lorne A. Page
openaire   +1 more source

Positron Annihilation in Thunderstorms

Nuclear Physics News, 2019
The positron, the antiparticle of the electron, was discovered in 1932 by David Anderson when a shower of cosmic rays hit his cloud chamber [1].
openaire   +1 more source