Abstract:
The N=88 isotones lie on the onset of nuclear deformation and have a complicated
nuclear structure. To better understand this region, the nuclear levels of
¹⁵⁰Sm were studied in three different β decay experiments. De-populating γ-rays
were measured using the 8π spectrometer, an array of 20 Compton suppressed Ge
detectors. Levels of ¹⁵⁰Sm were populated in varying degrees by three radioactive
sources: ¹⁵⁰Pm (J=1⁻, Q=3454 keV), ¹⁵⁰[superscript m]Eu (J=0⁻, Q=2303 keV), and ¹⁵⁰[superscipt g]Eu
(J=5⁻, Q=2261 keV), which were all produced at the 88" cyclotron located at
LBNL. Among several changes to the existing level structure were the addition of
a 0⁺ level identified at 1603.24 keV, as well as confirming another questioned 0⁺
assignment of the 1786.47 keV level. Angular correlation analysis was carried out
on many different transitions, allowing for spin assignments and the determination
of mixing ratios. The results from these three experiments provide extensive new
data, and give a fairly complete picture of nuclear levels below about 2 MeV and
J≤6. The theoretical interpretation of this particular nucleus is still open to question.
The data from these experiments, used in conjunction with other studies of
nuclei in this same mass region (which are currently underway), may provide further
insight into this transition region.
