Probing positron cooling in noble gases via annihilation $\gamma$ spectra

Abstract

$\gamma$ spectra for positron annihilation in noble-gas atoms are calculated using many-body theory for positron momenta up to the positronium-formation threshold. This data is used, together with time-evolving positron-momentum distributions determined in [arXiv:1706.01434 (2017)], to calculate the time-varying $\gamma$ spectra produced during positron cooling in noble gases. The $\gamma$-spectra and their $\bar{S}$ and $\bar{W}$ shape parameters are shown to be sensitive probes of the time evolution of the positron momentum distribution, and thus provide a means of studying positron cooling that is complementary to positron lifetime spectroscopy.

arXiv commentThis version contains minor update to references, otherwise unchanged

References in corpus (8)

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• Positron scattering and annihilation on noble gas atoms
• Proposed parameter-free model for interpreting the measured positron annihilation spectra of materials using a generalized gradient approximation
• $\gamma$-ray spectra and enhancement factors for positron annihilation spectra with core-electrons
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Cited by in corpus (6)

• Many-body theory for positronium-atom interactions
• Many-Body Theory Calculations of Positron Scattering and Annihilation in H${}_2$, N${}_2$ and CH${}_4$
• Positron cooling and annihilation in noble gases
• Time-Dependent Multi-Component Density Functional Theory for Coupled Electron-Positron Dynamics
• Positron cooling via inelastic collisions in CF${}_4$ and N${}_2$ gases
• Positron scattering and transport in liquid helium