Experimental study of isomeric intruder ½+ states 197,203At
Auranen, K., Uusitalo, J., Juutinen, S., Badran, H., Bisso, F. D., Cox, D., . . . Stolze, S. (2017). Experimental study of isomeric intruder ½+ states 197,203At. Physical Review C, 95 (4), 044311. doi:10.1103/PhysRevC.95.044311
Published inPhysical Review C
© 2017 American Physical Society. Published in this repository with the kind permission of the publisher.
A newly observed isomeric intruder ½ + state [ T ½ = 3.5 ( 6 ) ms ] is identified in 203 At using a gas-filled recoil separator and fusion-evaporation reactions. The isomer is depopulated through a cascade of E 3 and mixed M 1 / E 2 transitions to the 9 / 2 − ground state, and it is suggested to originate from the π ( s ½ ) − 1 configuration. In addition, the structures above the ½ + state in 203 At and 197 At are studied using in-beam γ -ray spectroscopy, recoil-decay tagging, and recoil-isomer decay tagging methods. The ½ + state is fed from 3 / 2 + and 5 / 2 + states, and the origin of these states are discussed.