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Perspective of Positron Annihilation Spectroscopy in Polymers
Macromolecules, 2013Positron annihilation spectroscopy (PAS) is a novel method that provides molecular-level information about complex macromolecular structure in a manner different from, but complementary to, conventional physical and chemical methodology. This paper presents a perspective of PAS in polymeric systems covering 12 aspects: historical, spacial, spherical ...
Y. C. Jean +3 more
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Positron Annihilation Spectroscopy at the LEPTA Facility
2014Since 2009 year the LEPTA facility at Joint Institute for Nuclear Research in Dubna is operated with positron beam. Today it is developed into two directions. The first one is getting orthopositronium flux in flight. Slow positrons from 22Na source are accumulated in Surko trap and then are injected into the ring where they should overlap with ...
Horodek, Paweł +4 more
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Positron-Annihilation-Induced Desorption Spectroscopy
2018PAID refers to ion desorption from solid surfaces initiated by ionization of surface atoms via electron–positron pair annihilation. It occurs even if the kinetic energy of incident positrons is lower than the threshold energies for electron-stimulated desorption (ESD) of ions initiated by electron-impact excitation of surface atoms.
Takayuki Tachibana, Yasuyuki Nagashima
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Positron-annihilation spectroscopy of native vacancies in as-grown GaAs
Physical Review B, 1988Native vacancy defects are studied in as-grown GaAs materials by positron-lifetime measurements. Direct evidence of native monovacancy-type defects is found in as-grown n-type Te-, Sn-, and Si-doped GaAs. However, the same evidence is not found in as-grown semi-insulating In- or Cr-doped GaAs or semi-insulating undoped GaAs or p-type GaAs(Zn).
, Corbel +4 more
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Positron annihilation response and broadband dielectric spectroscopy: Salol
The European Physical Journal E, 2011A phenomenological analysis of the ortho-positronium (o-Ps) annihilation from positron annihilation lifetime spectroscopy (PALS) and the dynamics from broadband dielectric spectroscopy (BDS) are reported on a small molecular glass former of intermediate H-bonding and fragility: salol.
Bartoš, J. +7 more
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Positron annihilation spectroscopy of methane monolayers adsorbed on graphite
Physical Review B, 1988Positron annihilation lifetime and Doppler-broadening energy spectra have been measured between 13 and 95 K for 0, 0.50, and 0.81 submonolayers of methane adsorbed on graphite. Both the surface positron lifetimes (\ensuremath{\sim}0.31 ns) and S parameter (central) of the Doppler-broadening energy spectra are sensitive to the solid-solid, solid-liquid,
, Wang, , Jean
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Positron annihilation spectroscopy using high‐energy photons
physica status solidi (a), 2010AbstractThe superconducting electron accelerator ELBE (Electron Linac with high Brilliance and low Emittance) at the Research Centre Dresden‐Rossendorf (Germany) serves as a high‐intensity bremsstrahlung photon‐source delivering a pulsed beam (26 MHz) with very short bunches (<5 ps).
Butterling, M. +10 more
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Positron Annihilation Spectroscopy (PAS)
2016A positron is an anti-particle of an electron and is annihilated with the electron in a sample. When lattice defects with open-volume exist in the samples, positrons are trapped there. Therefore, positron annihilation spectroscopy (PAS) is used to investigate lattice defects in samples.
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Metolose–PEG interaction as seen by positron annihilation spectroscopy
International Journal of Pharmaceutics, 2006The plasticizing effects of poly(ethylene glycol) (PEG 400) on methylcellulose (Metolose) cast films were studied by conventional physicochemical methods and positron annihilation spectroscopy. The PEG concentrations relative to the total polymer content were varied within the range 0-75% (w/w). At low concentrations (below 33.3%, w/w), the plasticizer
K, Pintye-Hódi +6 more
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Defect Characterization in Semiconductors with Positron Annihilation Spectroscopy
2010Positron annihilation spectroscopy is an experimental technique that allows the selective detection of vacancy defects in semiconductors, providing a means to both identify and quantify them. This chapter gives an introduction to the principles of the positron annihilation techniques and then discusses the physics of some interesting observations on ...
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