Photoproton cross section and angular distributions for /sup 12/C in the giant dipole resonance region

Journal Article · Sun Aug 01 04:00:00 EDT 1976 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.14.456· OSTI ID:7175278

Carchon, R; Van de Vyver, R; Ferdinande, H; Devos, J; Van Camp, E

The energy spectra and angular distributions of photoprotons from the /sup 12/C(..gamma.., p)/sup 11/B reaction have been measured at seven angles simultaneously, using 30 MeV bremsstrahlung. The giant dipole resonance peaks at 22.5 MeV, and reaches an absolute cross section value of 13.1 +- 0.8 mb. The anisotropy parameter a/sub 2/ from the Legendre polynomial expansion of the angular distributions has an average value of about - 0.55, but shows structure some especially around 25 MeV. On the other hand, the asymmetry coefficient a/sub 1/ is always positive and rises slowly with energy. Discussion of all coefficients leads to the conclusion that, although the photonuclear absorption mechanism in /sup 12/C leading to photoproton emission is dominated by the E1 component, a nonnegligible E2 contribution (about 2%) might be present. A recent coupled-channel calculation by Birkholz satisfactorily describes our results. (AIP)

• Research Organization: Laboratorium voor Kernfysica, Rijksuniversiteit te Gent, B-9000 Ghent, Belgium
• OSTI ID: 7175278
• Journal Information: Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 14:2; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651325* -- Nuclear Properties & Reactions
A=6-19
Experimental-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
ANISOTROPY
ASYMMETRY
BARYONS
BORON 11
BORON ISOTOPES
BREMSSTRAHLUNG
CARBON 12 TARGET
CROSS SECTIONS
DIPOLES
DISTRIBUTION
ELECTRIC DIPOLES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY SPECTRA
FERMIONS
FUNCTIONS
GIANT RESONANCE
HADRONS
ISOTOPES
LEGENDRE POLYNOMIALS
LIGHT NUCLEI
MEV RANGE
MEV RANGE 10-100
MULTIPOLES
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
ODD-EVEN NUCLEI
PHOTONUCLEAR REACTIONS
PHOTOPROTONS
POLYNOMIALS
PROTONS
RADIATIONS
RESONANCE
SPECTRA
STABLE ISOTOPES
TARGETS