The delayed neutron precursors in fission

Technical Report · Wed May 28 04:00:00 EDT 1958

OSTI ID:4258279

Pappas, Alexis C.

A survey of the experimental data on delayed neutron half lives and yields gives indication for the existence of a greater number of delayed neutron precursors than the six commonly accepted.This finds further support in the fact that the ratio of delayed neutron yield to cumulative fission yield of a delayed neutron precursor depends on the fissioning nuclide when computed from observed data. By means of a semitheoretica1 approach based on systemitics of β-decay energies, highly improved mass formulas, and theory for delayed neutron emission, the probability for delayed neutron emission is estimited. From this approach the distribution of delayed neutron precursors in a N, Z diagram is obtained. By coupling with known fission mass and charge-distribution curves the maximum possible number of delayed neutron precursors in thermal and low-energy fission is estimated to be in the vicinity of 50. Of the possible delayed neutron precursors about two thirds are odd Z nuclides and one third even Z nuclides. Of the elements concerned the largest amount of delayed neutron precursors is expected to be isotopes of bromine and iodine. (auth)

• Research Organization: Univ. of Oslo (Norway). Dept. of Chemistry
• NSA Number: NSA-13-006967
• OSTI ID: 4258279
• Report Number(s): A/CONF.15/P/583
• Country of Publication: Norway
• Language: English

Related Subjects

ATOMS
BETA DECAY
BROMINE ISOTOPES
DELAYED NEUTRONS
DISTRIBUTION
ELECTRIC CHARGES
EMISSION
ENERGY
EQUATIONS
FISSION
FISSION PRODUCTS
HALF- LIFE
IODINE ISOTOPES
MASS
NEUTRONS
NUCLEAR THEORY
NUCLEI
PHYSICS AND MATHEMATICS
PRODUCTION
THERMAL NEUTRONS