Year: 1993
Type: article
Abstract: The total cross section for positronium formation in helium for positrons of energies E from threshold (17.8 eV) to 250 eV has been measured using a gas cell transmission method. The results indicate that the cross section above E=60 eV is satisfactorily described by 0.5e -0.02E pi a 0 2 , tending to zero at energies close to 200 eV. The approximate description of the cross section at intermediate energies, falling as E -2.5 , is consistent with a number of theoretical predictions but is in conflict with earlier experiments, which show an E -1 behaviour. The implications of these measurements are discussed, with particular reference to the observed merging of the total cross sections for positron- and electron-helium scattering at intermediate energies.
Authors: N Overton, R J Mills, P G Coleman
Institution: University of East Anglia
Language: English
Topic: Atomic and Molecular Physics
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1978659698