Gamma-ray spectroscopy of neutron-rich products of heavy-ion collisions

Technical Report · Tue Aug 01 04:00:00 EDT 1995

DOI:https://doi.org/10.2172/166333· OSTI ID:166333

Carpenter, M. P.; Janssens, R. V.F.; Ahmad, I. ^[1]

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1. and others

Thick-target {gamma}{gamma} coincidence techniques are being used to explore the spectroscopy of otherwise hard-to-reach neutron-rich products of deep-inelastic heavy ion reactions. Extensive {gamma}{gamma} coincidence measurements were performed at ATLAS using pulsed beams of {sup 80}Se, {sup 136}Xe, and {sup 238}U on lead-backed {sup 122,124}Sn targets with energies 10-15% above the Coulomb barrier. Gamma-ray coincidence intensities were used to map out yield distributions with A and Z for even-even product nuclei around the target and around the projectile. The main features of the yield patterns are understandable in terms of N/Z equilibration. We had the most success in studying the decays of yrast isomers. Thus far, more than thirty new {mu}s isomers in the Z = 50 region were found and characterized. Making isotopic assignments for previously unknown {gamma}-ray cascades proves to be one of the biggest problems. Our assignments were based (a) on rare overlaps with radioactivity data, (b) on the relative yields with different beams, and (c) on observed cross-coincidences between {gamma} rays from light and heavy reaction partners. However, the primary products of deep inelastic collisions often are sufficiently excited for subsequent neutron evaporation, so {gamma}{gamma} cross-coincidence results require careful interpretation.

• Research Organization: Argonne National Lab., IL (United States)
• OSTI ID: 166333
• Report Number(s): ANL--95/14; ON: DE96000985
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
GAMMA SPECTROSCOPY
HEAVY ION REACTIONS
NUCLEAR STRUCTURE
PROGRESS REPORT
TIN ISOTOPES
YRAST STATES