In-Beam Study of ¹⁰⁹Sn

In-beam spectroscopic investigations of ¹⁰⁹Sn have been performed
using the reactions ⁵⁵Mn(⁵⁸Ni,3pn) and ¹⁰⁶Cd(alpha,n)
with E_58Ni= 240 MeV and E_alpha=23 MeV, respectively.
An extended level scheme of ¹⁰⁹Sn is presemted showing high-spin
states up to E_x ca. 8 MeV with J^pi=(41/2⁺).
The problem of the ¹⁰⁹Sn ground state has been solved identifying
a 12.8 keV transition deexciting the 7/2⁺ state to the 5/2⁺
g.s. A half-life of T_1/2=7(1) ns has been measured for
the 17/2⁺ state at E_x=2114 keV. The experimental
data are compared with the predictions of shell-model calculations.