Fission branch in sup 259 Lr and confirmation of sup 258 Lr and sup 259 Lr mass assignments

Journal Article · Sun Mar 01 00:00:00 EST 1992 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.45.1058· OSTI ID:7277373

Gregorich, K E; Hall, H L; Henderson, R A; Leyba, J D; Czerwinski, K R; Kreek, S A; Kadkhodayan, B A; Nurmia, M J; Lee, D M; Hoffman, D C ^[1]

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1. Nuclear Science Division, Lawrence Berkeley Laboratory, MS 70A-3307 and 94720 (United States)

The mass assignments for the activities previously assigned to {sup 259}Lr and {sup 258}Lr have been confirmed. The {sup 259}Lr and {sup 258}Lr were produced by the {sup 248}Cm({sup 15}N,4{ital n}) and {sup 248}Cm({sup 15}N,5{ital n}) reactions, respectively. The Lr {alpha} activities were measured directly using our rotating wheel system. Mass assignments were made by an {alpha}-daughter recoil catcher technique in which the {sup 255}Md and {sup 254}Md daughters were caught on aluminum foils placed directly above the rotating wheel. The {alpha} decay of the 20.07-h {sup 255}Fm and the 3.24-h {sup 254}Fm granddaughter activities in these aluminum foils were then measured and correlations with the decay of the Lr parent activities were made based on the distribution of the Fm activities among the Al foils, which corresponded to the half-lives of the parent Lr {alpha} activities. We have determined the half-lives for {sup 259}Lr and {sup 258}Lr to be 6.34{sub {minus}0.42}{sup +0.46} and 3.92{sub {minus}0.31}{sup +0.35} s, respectively. The spontaneous-fission branch in {sup 259}Lr was measured to be 23{plus minus}2%. The spontaneous-fission mass distribution appears to be broadly symmetric and the average total kinetic energy is estimated to be 200{plus minus}10 MeV.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 7277373
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 45:3; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

663210* -- Ground-State Radioactivity-- (1992-)
663590 -- Nuclear Mass Ranges-- A=220 & Above-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY
ALPHA DECAY RADIOISOTOPES
CALIFORNIUM 248
CALIFORNIUM ISOTOPES
CHARGED-PARTICLE REACTIONS
CURIUM 248 TARGET
DAYS LIVING RADIOISOTOPES
DECAY
EVEN-EVEN NUCLEI
FISSION
HEAVY ION REACTIONS
HEAVY NUCLEI
ISOTOPES
LAWRENCIUM 258
LAWRENCIUM 259
LAWRENCIUM ISOTOPES
MASS
NITROGEN 15 REACTIONS
NUCLEAR DECAY
NUCLEAR REACTIONS
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
SPONTANEOUS FISSION
SPONTANEOUS FISSION RADIOISOTOPES
TARGETS