Experimental identification of spin-parities and single-particle configurations in 257No and its alpha-decay daughter 253Fm.
alpha-gamma and alpha-electron coincidence spectroscopy for a short-lived heavy actinide nucleus (257)No (T(1/2) = 24.5 s) has been performed using a gas-jet transport system and an on-line isotope separator. Spin-parities of excited states in (253)Fm fed by the alpha decay of (257)No have been identified on the basis of the measured internal conversion coefficients. The nu3/2(+)[622] configuration has been assigned to the ground state of (257)No as well as to the 124.1 keV level in (253)Fm. It was found that the ground-state configuration of (257)No is different from that of lighter N = 155 isotones.
Asai
M
M
Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki.
Tsukada
K
K
Sakama
M
M
Ichikawa
S
S
Ishii
T
T
Nagame
Y
Y
Nishinaka
I
I
Akiyama
K
K
Osa
A
A
Oura
Y
Y
Sueki
K
K
Shibata
M
M