Independent isomeric yield ratio of /sup 148/Pm in fission of the moderately excited /sup 236/U compound nucleus as a measure of fragment angular momentum

Journal Article · Fri Jul 01 04:00:00 EDT 1977 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.16.254· OSTI ID:7219481

Aumann, D C; Gueckel, W; Nirschl, E; Zeising, H

The independent yield ratio of 41.3-day /sup 148/Pm/sup m/ (6-) and 5.37-day /sup 148/Pm/sup g/ (1-) has been measured radiochemically for fission of /sup 233/U and /sup 235/U induced by thermal neutrons and for fission of /sup 232/Th by /sup 4/He ions of 26--42 MeV. The values of the /sup 148/Pm isomer were 3.0 +- 0.5 and 2.6/sup +0.9//sub -0.5/ for the thermal-neutron-induced fission of /sup 233/U and /sup 235/U, respectively, and 6.8 +- 1.2, 6.6 +- 0.7, 5.3 +- 0.5, 8.5 +- 0.9, and 8.5 +- 0.9 for fission of /sup 232/Th by /sup 4/He ions of 25.8, 29.1, 31.8, 37.0, and 41.4 MeV, respectively. On the basis of the measured independent yield ratios the average intrinsic angular momentum of the primary fission fragments (which lead by the emission of prompt neutrons and ..gamma.. rays to the secondary fragment /sup 148/Pm) was estimated by means of a simple statistical-model analysis based on the formalism developed by Huizenga and Vandenbosch. The following values for the average intrinsic spin of the primary fragment were obtained: (10.8 +- 0.9) h and (10.0/sup +1.6//sub -1.1/) h for thermal-neutron-induced fission of /sup 233/U and /sup 235/U, respectively, and (16.5 +- 1.5) h, (16.3 +- 0.9) h, (14.6 +- 0.7) h, (19.9 +- 1.1) h, and (19.9 +- 1.1) h for fission of /sup 232/Th by /sup 4/He ions of 25.8, 29.1, 31.8, 37.0, and 41.4 MeV, respectively. The results show that a fraction of the angular momentum of the fissioning nucleus appears as intrinsic spin of the primary fragments when the angular momentum of the fissioning nucleus is increased as in the case of the /sup 4/He-ion-induced fission. A summary of all published independent isomer yield ratio studies which were used for deducing fission fragment angular momenta is given.

• Research Organization: Institut fuer Radiochemie, Technische Universitaet Muenchen, 8046 Garching b. Muenchen, Germany
• OSTI ID: 7219481
• Journal Information: Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 16:1; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

652026* -- Nuclear Properties & Reactions
A=220 & above
Experimental-- Spontaneous & Induced Fission-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
ALPHA REACTIONS
ANGULAR MOMENTUM
BARYON REACTIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHARGED-PARTICLE REACTIONS
DAYS LIVING RADIOISOTOPES
ENERGY RANGE
EVEN-EVEN NUCLEI
FISSION
FISSION FRAGMENTS
FISSION ISOMERS
FISSION YIELD
GAMMA SPECTRA
HADRON REACTIONS
HEAVY NUCLEI
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 10-100
NEUTRON REACTIONS
NUCLEAR FRAGMENTS
NUCLEAR REACTION YIELD
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
ODD-ODD NUCLEI
PROMETHIUM 148
PROMETHIUM ISOTOPES
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
SPECTRA
STATISTICAL MODELS
TARGETS
THERMAL FISSION
THORIUM 232 TARGET
URANIUM 233 TARGET
URANIUM 236
URANIUM 236 TARGET
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES
YIELDS