Positron annihilation in gaseous nitrogen and nitrogen-neon mixtures at 77 K

Journal Article · Sun Oct 01 04:00:00 EDT 1978 · Phys. Rev., A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.18.1426· OSTI ID:6680930

Sharma, S C; McNutt, J D

Annihilation lifetime spectra have been measured for positrons in N/sub 2/ gas at 77 K at densities in the range 1.9--3.6 amagat, and in N/sub 2/-Ne gas mixtures at 77 K having N/sub 2/ partial densities in the range 0.5--3.7 amagat and with Ne concentrations in the range 0.34--0.98. The annihilation rate of positrons with N/sub 2/ was found to be independent of the Ne concentration in the gas mixtures. (Z/sub eff/)/sub N/2 remains constant at 40.0 +- 0.9 at N/sub 2/ densities below about 2.3 amagat, but increases to about 108 at 3.7 amagat. Shoulder regions in the lifetime spectra of positrons in N/sub 2/ and in N/sub 2/-Ne mixtures have been observed which have a constant width of about 14 nsec amagat at N/sub 2/ densities below about 2 amagat, but which increase to about 24 nsec amagat at 3.7 amagat of N/sub 2/. For N/sub 2/ densities in the range 2--3.7 amagat, the measured shoulder widths correspond to a constant time of about 7 nsec. The slow-positron annihilation rates and the shoulder widths are discussed in terms of the self-trapping of positrons within clusters of N/sub 2/ molecules.

• Research Organization: Department of Physics, The University of Texas at Arlington, Arlington, Texas 76019
• OSTI ID: 6680930
• Journal Information: Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 18:4; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640303* -- Atomic
Molecular & Chemical Physics-- Positronium
Muonium
& Muonic & Mesic Atoms & Molecules
74 ATOMIC AND MOLECULAR PHYSICS
ANNIHILATION
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
ATOM COLLISIONS
BASIC INTERACTIONS
BINARY MIXTURES
COLLISIONS
CRYOGENIC FLUIDS
DISPERSIONS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
FLUIDS
INTERACTIONS
LEPTONS
LIFETIME
MIXTURES
MOLECULE COLLISIONS
NEON
NITROGEN
NONMETALS
POSITRON COLLISIONS
POSITRON-ATOM COLLISIONS
POSITRON-MOLECULE COLLISIONS
POSITRONS
RARE GASES