Spectroscopy of {sup 257}Rf

Journal Article · Mon Jun 15 00:00:00 EDT 2009 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.79.064319· OSTI ID:21293747

Qian, J; Heinz, A; Winkler, R ^[1]; Khoo, T L; Janssens, R V. F.; Peterson, D; Seweryniak, D; Ahmad, I; Back, B B; Carpenter, M P; Greene, J P; Jiang, C L; Kondev, F G; Lauritsen, T; Lister, C J; Robinson, A; Savard, G; Scott, R; Vondrasek, R; Wang, X ^[2]

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1. WNSL, Yale University, New Haven, Connecticut 06511 (United States)
2. Argonne National Laboratory, Illinois 60439 (United States)

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 {alpha} 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} {mu}s, was discovered by detecting internal conversion electrons followed by {alpha} 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 {alpha} 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.

• OSTI ID: 21293747
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 79, Issue 6; Other Information: DOI: 10.1103/PhysRevC.79.064319; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA DECAY
ATOMIC NUMBER
BRANCHING RATIO
DAUGHTER PRODUCTS
ELECTRON CAPTURE DECAY
ELECTRONS
EXCITATION
EXCITED STATES
FISSION
HALF-LIFE
INTERNAL CONVERSION
ISOMERS
ISOTONIC NUCLEI
ISOTOPE PRODUCTION
KEV RANGE
LAWRENCIUM 257
LEAD 208 TARGET
MASS
NEUTRON EMISSION
NOBELIUM 253
RUTHERFORDIUM 257
SPECTROSCOPY
TITANIUM 50