Internal pair conversion in heavy nuclei

Journal Article · Sun Jun 01 04:00:00 EDT 1997 · Physical Review, C

OSTI ID:509118

Positrons and electrons from the internal pair conversion (IPC) decay of states populated in near-barrier collisions of very heavy ions have been studied using the APEX spectrometer. Using inelastic {sup 206}Pb+{sup 206}Pb scattering at 5.90 MeV/nucleon, the gamma and IPC branches of the well-known E1 decay of the first J{sup {pi}}=3{sup {minus}} state were kinematically reconstructed and the IPC-to-gamma branching ratio was determined to be {beta}=(4.0{plus_minus}0.7){times}10{sup {minus}4}. We have also performed experiments with actinide beams or targets; {sup 238}U+{sup 181}Ta, {sup 208}Pb+{sup 238}U, {sup 208}Pb+{sup 232}Th, and {sup 238}U+{sup 232}Th, which resulted in the observation of new gamma-ray transitions from high-lying states in {sup 232}Th and {sup 238}U. None of these were populated with sufficient strength such that IPC could produce statistically significantly peaks in positron-electron sum energy spectra. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 509118
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 6 Vol. 55; ISSN PRVCAN; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BRANCHING RATIO
ELECTRONS
ENERGY SPECTRA
GAMMA RADIATION
HEAVY ION REACTIONS
INELASTIC SCATTERING
INTERNAL CONVERSION
LEAD 206 REACTIONS
LEAD 206 TARGET
LEAD 208 REACTIONS
POSITRONS
TANTALUM 181 TARGET
THORIUM 232 TARGET
URANIUM 238 REACTIONS
URANIUM 238 TARGET