| Popis: |
The level structure of the N=60 isotone $^{99}\mathrm{Y}$ has been studied via the decay of $^{99}\mathrm{Sr}$. \ensuremath{\gamma} singles and \ensuremath{\gamma}-\ensuremath{\gamma} coincidence measurements have resulted in 71 \ensuremath{\gamma} transitions placed in a decay scheme with 26 levels. \ensuremath{\gamma}-ray multiscaling measurements give a $^{99}\mathrm{Sr}$ half-life of 270\ifmmode\pm\else\textpm\fi{}10 ms. Five rotational bands, including the previously identified K=(5/2) ground-state band, have been identified in $^{99}\mathrm{Y}$. Nilsson orbitals, with bandhead energies in keV in parentheses, associated with these five bands are (5/2)[422] (0), (5/2)[303] (487), (3/2)[301] (536), (1/2) [431] (1011), and (3/2)[431] (1119). The rotational features are consistent with an axially symmetric deformation in the range 0.3 to 0.4. The characteristics of these bands and their associated \ensuremath{\gamma}-ray transitions are discussed. |
