Precision Determination of Nuclear Energy Levels in Heavy Elements

Abstract

The low-lying energy levels in 32 isotopes between $Z=62$ and $Z=75$ have been studied using a high-precision bent quartz crystal spectrograph to determine gamma-ray energies. The gamma rays were produced by the electric (or Coulomb) excitation process. The high proton-beam current of the A-48 accelerator was used to provide the intense sources necessary for these experiments. With this technique, energies in the 100-kev region can be determined with a precision of about one part in 2000. A comparison of the results with the unified model of nuclear structure is given.