Cross sections for positronium formation in gases

Charlton, M.; Griffith, T C; Heyland, G R; Lines, K S

doi:10.1088/0022-3700/12/20/009

Cited by 16 publications

(3 citation statements)

References 9 publications

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“…It should be mentioned in passing that deviations from this value of k were noted by Charlton et a1 (1980a) in their study of e--He scattering. In this case, however, much lower gas densities were employed than those used by Griffith et al (1979) and all results from UCL using the localised scattering system which are discussed later in this section have been normalised using the original value deduced by those authors.…”

Section: Total Cross Sectionsmentioning

confidence: 99%

Experimental studies of positrons scattering in gases

Charlton¹

1985

Rep. Prog. Phys.

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166

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The current status of certain aspects of positron scattering in gases is reviewed. A brief resume of the experimental techniques used in this field is also given.Results for total scattering cross sections in a number of gases are presented along with a detailed discussion of potential systematic errors which can affect such measurements. Important features of the cross sections are pointed out and comparisons are made with electron scattering data.Results from experiments which go beyond total cross section determinations are discussed. Emphasis is placed upon recent measurements of positronium formation cross sections.Recent positron lifetime studies in dense gases are reviewed. The subjects covered include positron annihilation in clusters, ortho-positronium annihilation in bubbles and positronium formation in spurs.

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Section: Total Cross Sectionsmentioning

confidence: 99%

Experimental studies of positrons scattering in gases

Charlton¹

1985

Rep. Prog. Phys.

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166

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“…Conventionally, the fraction of positrons forming positronium in gases prior to annihilation is deduced from the intensity of the long-lived orthopositronium component in the lifetime spectra (Griffith and Heyland 1978). While the measured fractions in helium, neon and argon are compatible with the Ore model (Ore 1949, Griffith andHeyland 1978), those for krypton and xenon are anomalously below the prediction of the model (Coleman et a2 1975), even though the positron-atom scattering experiments in the rare gases indicate larger positronium formation cross sections for the heavier atoms (Charlton et al 1979, 1983, Dabaneth et a1 1982.…”

Section: Introductionmentioning

confidence: 94%

Evidence for normal formation of positronium in gaseous Xe

Kakimoto

Hyodo

1988

J. Phys. B: At. Mol. Opt. Phys.

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Angular correlation of photons from positrons annihilating in the rare gases (helium, neon, argon, krypton and xenon) have been measured in order to investigate positronium formation in these gases at low pressures (0.1, 0.2, 0.4, 0.7 and 1.0atm for xenon and 0.2 and 1.0 atm for the other gases). A piece of silica aerogel was used to stop positrons in such a thin region that high-resolution angular correlation measurements could be performed with high statistics regardless of the density of the gases. Formation of parapositronium in xenon has been found to be higher than in the other gases under the present experimental conditions. The result, apparently contradictory to the low orthopositronium fraction observed in lifetime experiments, is consistent with the Ore model of the positronium formation and the measured positronium formation cross sections for the gases. By applying a static magnetic field, the fraction of orthopositronium in xenon has been also measured. It has been confirmed that xenon has a strong quenching effect on orthopositronium. This is consistent with the reported dearth of long-lived components in the positron lifetime spectra in xenon.

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“…Ps has a central role in the study of matter-antimatter gravitational interactions. On one hand, Ps has been identified as a promising intermediate system for antihydrogen production via a charge-exchange reaction with an antiproton [2][3][4]. Specifically, the AEgIS [5][6][7] and GBAR collaborations [8] are exploring the possibility of producing antihydrogen following the charge-exchange reaction scheme to experimentally probe the antimatter gravitational acceleration.…”

Section: Introductionmentioning

confidence: 99%

A ∼100 μm-resolution position-sensitive detector for slow positronium

Amsler

Antonello

Belov

et al. 2019

Nuclear Instruments and Methods in Physics Research Section B:

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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. A spatial resolution of ± (88 5) μm on the position of the ionized positronium -in the plane perpendicular to a 1.0 T magnetic field-is obtained. The possibility to apply the detection scheme for monitoring the emission into vacuum of positronium from positron/positronium converters, imaging posihttps://doi.

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Cross sections for positronium formation in gases

Cited by 16 publications

References 9 publications

Experimental studies of positrons scattering in gases

Experimental studies of positrons scattering in gases

Evidence for normal formation of positronium in gaseous Xe

A ∼100 μm-resolution position-sensitive detector for slow positronium

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Cross sections for positronium formation in gases

Cited by 16 publications

References 9 publications

Experimental studies of positrons scattering in gases

Experimental studies of positrons scattering in gases

Evidence for normal formation of positronium in gaseous Xe

A ∼100 μm-resolution position-sensitive detector for slow positronium

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Product

Resources

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A ∼100 μm-resolution position-sensitive detector for slow positronium