Applications and misapplications of the channel-capture formalism of direct neutron capture

Conference · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5469028

Raman, S; Lynn, J E

We discuss the channel-capture approximation of slow neutron direct-capture theory. We show that this approximation gives a generally good representation of the neutron capture cross sections for several electric dipole transitions in a broad range of nuclides from A = 9 to A = 136; these are mostly near-spherical nuclei. Despite this body of agreement, we examine the accuracy we can expect from the simple channel-capture theory. Comparison with calculations of the potential-capture cross section from physically more realistic optical model calculations show that, in general, the channel-capture cross section can be up to approx. =40% in error. In cases where the expected channel-capture cross section is much smaller than the ''hard-sphere'' capture cross-section estimate, the disagreement with potential capture can be much worse than this. Also, in these cases, compound-nucleus capture can be of comparable or greater magnitude. These effects have been shown to completely undermine recent attempts to determine nuclear interaction radii for targets, such as /sup 12/C and /sup 9/Be, by application of the channel-capture formula to capture cross-section data. 20 refs.

• Research Organization: Oak Ridge National Lab., TN (USA); UKAEA Atomic Energy Research Establishment, Harwell
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5469028
• Report Number(s): CONF-850635-1; ON: DE85013992
• Country of Publication: United States
• Language: English

Related Subjects

653003* -- Nuclear Theory-- Nuclear Reactions & Scattering
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALINE EARTH ISOTOPES
BARYON REACTIONS
BERYLLIUM 9
BERYLLIUM ISOTOPES
CAPTURE
CARBON 12 TARGET
COMPOUND NUCLEI
CROSS SECTIONS
E1-TRANSITIONS
ENERGY-LEVEL TRANSITIONS
EVEN-ODD NUCLEI
HADRON REACTIONS
ISOTOPES
LIGHT NUCLEI
MULTIPOLE TRANSITIONS
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
OPTICAL MODELS
STABLE ISOTOPES
TARGETS