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A ∼100 μm-resolution position-sensitive detector for slow positronium [PDF]
Nuclear Instruments & Methods in Physics Research B, 2019 In this work we describe a high-resolution position-sensitive detector for positronium. The detection scheme is based on the photoionization of positronium in a magnetic field and the imaging of the freed positrons with a Microchannel Plate assembly.
Sebastian Gerber +2 more
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Compton Disintegration of Positronium
Moscow University Physics Bulletin, 2023We study the Compton disintegration of positronium in comparison with the same of hydrogen. The initial photon energy of a few keV allows one to apply the non-relativistic approach and use A2 approximation. Interesting features in the behavior of various differential cross sections are observed. In particular, the conditions were found, under which the
I. S. Stepantsov +2 more
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Journal of the Physical Society of Japan, 2001
The s-wave scattering parameters for the Positronium–Positronium (Ps–Ps) interaction are estimated semi-phenomenologically with the long-range van der Waals force and the short-range repulsive potential. The obtained values of the scattering length and the effective range are a ∼0.44 nm, and r 0 ∼0.2 nm for the symmetric channel.
Takahiko Miyakawa
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The s-wave scattering parameters for the Positronium–Positronium (Ps–Ps) interaction are estimated semi-phenomenologically with the long-range van der Waals force and the short-range repulsive potential. The obtained values of the scattering length and the effective range are a ∼0.44 nm, and r 0 ∼0.2 nm for the symmetric channel.
Takahiko Miyakawa
exaly +2 more sources
Journal of Mathematical Physics, 1965
By means of an inequality providing an upper bound for the norm of integral operators, it is shown that the Bethe-Salpeter equation for bound states of the electron-positron system (in the ladder approximation) admits solutions associated with a discrete spectrum of binding energies.
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By means of an inequality providing an upper bound for the norm of integral operators, it is shown that the Bethe-Salpeter equation for bound states of the electron-positron system (in the ladder approximation) admits solutions associated with a discrete spectrum of binding energies.
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Thermalisation of Positronium in Polymers
Materials Science Forum, 1997A new model is presented which describes the annihilation of positronium (Ps) in polymers. Ps is formed in the bulk and is trapped into the free volume holes with epithermal initial energy and it thermalises towards its ground state during its lifespan through elastic collisions with the inner walls, This thermalisation is characterised by an ...
C. Dauwe +6 more
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The production of molecular positronium
Nature, 2007It has been known for many years that an electron and its antiparticle, the positron, may together form a metastable hydrogen-like atom, known as positronium or Ps (ref. 1). In 1946, Wheeler speculated that two Ps atoms may combine to form the di-positronium molecule (Ps2), with a binding energy of 0.4 eV.
D B, Cassidy, A P, Mills
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A new model of positronium formation: Resonant positronium formation
Journal of Chemical Physics, 1990‘‘Resonant model,’’ a new model of positronium (Ps) formation is proposed. The first stage of Ps formation is the inelastic collisions of e+ through formation of an intermediate state (M*.e+) by resonant energy absorption and e+ attachment. The second stage of Ps formation involves thermalized e+ and loosely bound electrons (excess electrons, excited ...
Zhicheng Zhang, Yasuo Ito
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Materials Science Forum, 2012
A review of data about positron annihilation lifetime in normal alkanes is presented. It was found that positronium in rigid phase locates in the interlamellar gap, while in the rotator one in free volumes inside lamellae. Interesting effects seem to be: identity of o-Ps lifetime in rotator and liquid phase in long chain alkanes; appearance of ...
Goworek, T. +3 more
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A review of data about positron annihilation lifetime in normal alkanes is presented. It was found that positronium in rigid phase locates in the interlamellar gap, while in the rotator one in free volumes inside lamellae. Interesting effects seem to be: identity of o-Ps lifetime in rotator and liquid phase in long chain alkanes; appearance of ...
Goworek, T. +3 more
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Physical Review Letters, 1996
The total cross section ${\ensuremath{\sigma}}_{T}$ for orthopositronium (o-Ps) scattering from argon gas has been measured directly for the first time using a variable energy o-Ps beam in the range 16--95 eV. The cross section is found to rise from a value of approximately $9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}20}$ to $15\ifmmode ...
, Zafar +3 more
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The total cross section ${\ensuremath{\sigma}}_{T}$ for orthopositronium (o-Ps) scattering from argon gas has been measured directly for the first time using a variable energy o-Ps beam in the range 16--95 eV. The cross section is found to rise from a value of approximately $9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}20}$ to $15\ifmmode ...
, Zafar +3 more
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Muonium and positronium potentials
Physical Review D, 1989Muonium and positronium potentials with radiative corrections are derived from the scattering operator, and general results for the spectra of these systems to order ${\ensuremath{\alpha}}^{3}{R}_{\ensuremath{\infty}}$ are obtained. We also compare our results with those obtained earlier with the Bethe-Salpeter approach, and find a discrepancy in the ...
, Gupta, , Repko, , Suchyta
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