Recent results on electron-positron production in heavy ion collisions

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Bulletin of the American Physical Society

OSTI ID:255594

Wuosmaa, A

The positron and positron-electron line phenomena in heavy ion collisions have been investigated with a new device - APEX - specifically designed for this purpose. Earlier work reporting the observation of line structure in the spectra of positrons and sharp lines in sum-energy spectra of coincident positrons and electrons, produced in low-energy collisions of very heavy nuclei, has provided a persistent puzzle. New data obtained with APEX for {sup 238}U + {sup 181}Ta and {sup 238}U + {sup 232}Th, measured under similar conditions to the previous experiments, do not show evidence for the reported lines. In the specific case of the isolated two-body decay of a neutral object, the cross section limits obtained are far below those implied by the previous results. A measurement of internal pair conversion from a 1.84 MeV transition in {sup 206}Pb was used to verify the correct functioning of APEX.

• OSTI ID: 255594
• Report Number(s): CONF-9510116--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 10 Vol. 40; ISSN BAPSA6; ISSN 0003-0503
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ELECTRON PAIRS
PAIR PRODUCTION
TANTALUM 181 TARGET
THORIUM 232 TARGET
URANIUM 238 REACTIONS