Nonstatistical {gamma} emission in {sup 3}He- and {alpha}-induced reactions

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.53.1759· OSTI ID:282134

Behr, J A; Snover, K A; Gossett, C A; Feldman, G; Gundlach, J H; Kicinska-Habior, M ^[1]

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1. Nuclear Physics Laboratory, University of Washington, Seattle, Washington 98195 (United States)

We have measured inclusive {gamma}-ray production cross sections for {sup 3}He- and {alpha}-induced reactions on various targets in the mass range {ital A}=61{endash}181 at projectile energies of 11{endash}27 MeV. Except for {alpha}-induced yields on the lightest targets, all reactions show high-energy {gamma}-ray yields 1{endash}3 orders of magnitude larger than can be obtained from statistical model calculations. Angular distributions are strongly forward peaked in the center of mass frame for the highest {gamma}-ray energies, providing model-independent evidence for a nonstatistical reaction mechanism. Calculations of direct radiative capture and semidirect excitation of the giant dipole resonance can qualitatively reproduce the angular distributions but cannot reproduce either the dependence of the {gamma}-ray cross sections on {ital E}{sub {gamma}} or the target dependence of the absolute cross sections. The {sup 12}C({sup 3}He,{gamma}{sub 0}){sup 15}O reaction was found to change from predominantly statistical to predominantly direct over this bombarding energy range. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 282134
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 4 Vol. 53; ISSN PRVCAN; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALPHA REACTIONS
ANGULAR DISTRIBUTION
CROSS SECTIONS
DIPOLES
GAMMA RADIATION
GIANT RESONANCE
HELIUM 3 REACTIONS
MASS
PROJECTILES
STATISTICAL MODELS