One- and three-quasiparticle states in /sup 249/Cf populated by the electron capture decay of 1. 70-h /sup 249/Es

Journal Article · Thu Jul 01 04:00:00 EDT 1976 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.14.218· OSTI ID:7278915

Ahmad, I; Sjoblom, R K; Fields, P R

The level structure of /sup 249/Cf has been investigated by measuring the ..gamma.. rays and conversion electrons associated with the electron capture decay of 1.70-h /sup 249/Es. The ..gamma..-ray spectra were measured with a 2-cm/sup 2/ x 5-mm planar and a 25-cm/sup 3/ coaxial Ge(Li) detector and the conversion-electron spectra were measured with a cooled Si(Li) detector. Forty-six ..gamma.. rays were identified and multipolarities of most of the transitions were deduced. The half-life of /sup 249/Es was determined from the decay rate of the 379.5-keV photopeak and was found to be 102.2 +- 0.6 min. The logft values for the observed electron capture transitions were derived from the measured electron capture intensities. On the basis of the present work the following intrinsic states were identified: 9/2-(734), 0; 5/2+(622), 145.0; 7/2+(624), 379.5; 7/2+(613), 443.0; K..pi..=5/2-, 813.2; 9/2+(615), 1007.9; and K..pi..=7/2-, 1218.5. The 5/2- band at 813.2 keV has been interpreted as the ..gamma..-vibrational band coupled to the 9/2-(734) ground state. The 7/2- state at 1218.5 keV has been interpreted as a three-quasiparticle state with configuration )p(633)7/2+; p(521)3/2-; n(622)3/2+closing-brace/sub 7///sub 2/-. This is the first time a three-quasiparticle state in an actinide nucleus has been identified. An enhancement in the B (E3) value of the 145.0..-->..0 transition has been observed which suggests collective admixture in the 145.0-keV state. From the experimental B (E3) value the admixture (amplitude squared) of the )9/2-(734)direct-product2/sup -/closing-brace/sub 5///sub 2/+ configuration in the 145.0-keV state has been derived to be approx.29%, in excellent agreement with the results of (d,d') reaction studies. (AIP)

• Research Organization: Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
• OSTI ID: 7278915
• Journal Information: Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 14:1; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

652022 -- Nuclear Properties & Reactions
A=220 & above
Experimental-- Radioactive Decay-- (-1987)
652023* -- Nuclear Properties & Reactions
A=220 & above
Experimental-- Energy Levels & Transitions-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BARYONS
BASIC INTERACTIONS
BETA DECAY
BETA DECAY RADIOISOTOPES
CALIFORNIUM 249
CALIFORNIUM ISOTOPES
CHARGED-PARTICLE REACTIONS
DECAY
DEUTERON REACTIONS
EINSTEINIUM 249
EINSTEINIUM ISOTOPES
ELECTRON CAPTURE DECAY
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTARY PARTICLES
ENERGY RANGE
EVEN-ODD NUCLEI
FERMIONS
FT VALUE
GAMMA SPECTROSCOPY
HADRONS
HALF-LIFE
HEAVY NUCLEI
HOURS LIVING RADIOISOTOPES
INTERACTIONS
ISOTOPES
LEPTONIC DECAY
MEV RANGE
MEV RANGE 10-100
NEUTRONS
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
ODD-EVEN NUCLEI
PARTICLE DECAY
RADIOISOTOPES
SPECTROSCOPY
WEAK INTERACTIONS
WEAK PARTICLE DECAY
YEARS LIVING RADIOISOTOPES