THEORY OF RADIATIVE CAPTURE REACTIONS

Journal Article · Mon Jun 01 04:00:00 EDT 1959 · Nuclear Phys.

DOI:https://doi.org/10.1016/0029-5582(59)90304-9· OSTI ID:4217973

Lane, A M

Starting from an exact dispersion theory, it is shown how cross sections for capture by various mechanisms may be extracted by appropriate specializations of the theory. The cross section for compound nucleus'' capture is derived by the usual assumption of random signs for matrix elements (reduced width amplitudes). It is pointed out that this cross section reduces to the Weisskopf- Ewing formula that is commonly used only after a second assumption is made, viz., that the density of energy levels of spin I in the final nucleus is proportional to (2I + 1). The cross section for direct'' capture, which has previously been derived phenomenologically, is extracted from the exact formalism by technigues developed by Bloch and by Brown and de Dominicis for treating other kinds of direct reactions. Attention is drawn to the fact that the integrals in the matrix elements of the electromagnetic interaction should be taken to infinity, thereby incorporating a contribution from the channels besides the usual one from the nuclear interior. This channel contribution is shown to be very important in practice. (auth)

• Research Organization: Atomic Energy Research Establishment, Harwell, Berks, Eng.
• NSA Number: NSA-13-018517
• OSTI ID: 4217973
• Journal Information: Nuclear Phys., Journal Name: Nuclear Phys. Vol. Vol: 11
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CAPTURE
COMPOUND NUCLEI
CROSS SECTIONS
DIRECT REACTIONS
DISPERSION THEORY
DISTRIBUTION
ELECTROMAGNETIC FIELDS
ENERGY LEVELS
EQUATIONS
EXCITATION
GAMMA RADIATION
INTERACTIONS
MATRICES
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEAR THEORY
NUCLEI
PHYSICS AND MATHEMATICS
SPIN