Distribution of delayed neutron yields versus proton, neutron, and mass numbers: application to proton pairing in fission yields

Journal Article · Fri Jun 01 04:00:00 EDT 1984 · Nucl. Sci. Eng.; (United States)

OSTI ID:6190333

Reeder, P L; Warner, R A

Evaluated delayed neutron emission probabilities for 74 precursors and estimated probabilities for another 174 precursors have been combined with ENDF/B-V fission yields to map out delayed neutron yields as a function of mass number, proton number, and neutron number. For all fissioning systems, more than 90% of the delayed neutron yield comes from precursors with measured P /SUB n/ values. Most of the remaining yield comes from the precursors /sup 88/As, /sup 100 -103/Y, and /sup 137/Sb. High priority should be given to P /SUB n/ measurements for these precursors. Periodic peaks about five mass numbers apart are seen when delayed neutron yields are plotted versus mass number. This behavior is explained by the very strong enhancement of yields from odd Z precursors. Even Z precursors contribute <10% of the total delayed neutron yield. Plots of delayed neutron yields versus neutron number show dramatic decreases at the closed shell numbers 50 and 82 and smaller effects at subshell numbers 40 and 56. A procedure based on calculated and total delayed neutron yields is proposed for determining proton pairing factors in the fission yield model.

• Research Organization: Battelle Pacific Northwest Laboratories, Richland, Washington
• OSTI ID: 6190333
• Journal Information: Nucl. Sci. Eng.; (United States), Journal Name: Nucl. Sci. Eng.; (United States) Vol. 87:2; ISSN NSENA
• Country of Publication: United States
• Language: English

Related Subjects

651722 -- Nuclear Properties &amp; Reactions
A=90-149
Experimental-- Radioactive Decay-- (-1987)
652026* -- Nuclear Properties &amp; Reactions
A=220 &amp; above
Experimental-- Spontaneous &amp; Induced Fission-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANTIMONY ISOTOPES
ARSENIC ISOTOPES
ATOMIC NUMBER
BARYONS
DELAYED NEUTRON PRECURSORS
DELAYED NEUTRONS
DISTRIBUTION
ELEMENTARY PARTICLES
EMISSION
EMISSION SPECTRA
FERMIONS
FISSION NEUTRONS
FISSION YIELD
HADRONS
INTERACTIONS
ISOTOPES
MASS NUMBER
MATHEMATICAL MODELS
NEUTRON EMISSION
NEUTRONS
NUCLEAR REACTION YIELD
NUCLEONS
PAIRING INTERACTIONS
PROBABILITY
PROTONS
RADIOISOTOPES
SPECTRA
YIELDS
YTTRIUM ISOTOPES