Spectroscopy of {sup 257}Rf.

Journal Article · Mon Jun 01 04:00:00 EDT 2009 · Phys. Rev. C

DOI:https://doi.org/10.1103/PhysRevC.79.064319· OSTI ID:962070

Qian, J; Heinz, A; Khoo, T L; Janssens, R V. F.; Peterson, D; Seweryniak, D; Ahmad, I; Asai, M; Back, B B; Carpenter, M P; Garnsworthy, A B; Greene, J P; Hecht, A A; Jiang, C L; Kondev, F G; Lauritsen, T; Lister, C J; Robinson, A; Savard, G; Scott, R ; Vondrasek, R; Wang, X; Winkler, R; Zhu, S

The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti,n){sup 257}Rf. Reaction products were separated and identified by mass. Delayed spectroscopy of {sup 257}Rf and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on hindrance factors. The excitation energy of the 1/2{sup +}[620] configuration in {sup 253}No is proposed. The energy of this 1/2{sup +} state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup +42} {micro}s, was discovered by detecting internal conversion electrons followed by decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1{sub -1.3}{sup +2.4} s, followed by decay, was also observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf. Fission of {sup 257}Rf was unambiguously detected, with a branching ratio of b{sub Rf}{sup SF} = 0.02 {+-} 0.01.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 962070
• Report Number(s): ANL/PHY/JA-63918
• Journal Information: Phys. Rev. C, Journal Name: Phys. Rev. C Journal Issue: Jun. 2009 Vol. 79; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ATOMIC NUMBER
BRANCHING RATIO
CONFIGURATION
DAUGHTER PRODUCTS
DECAY
ELECTRON CAPTURE
ELECTRONS
EXCITATION
EXCITED STATES
FISSION
HALF-LIFE
INTERNAL CONVERSION
ISOTONIC NUCLEI
SPECTROSCOPY