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 in
Physical Review CDate
2017Copyright
© 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.