Nuclear orientation study of 166Hom

Angular distributions have been measured for 25 gamma rays emitted in the decay of ¹⁶⁶Ho^m oriented at low temperatures in paramagnetic neodymium ethyl sulfate and in ferromagnetic Ho metal. The hyperfine Hamiltonians are discussed and parameters describing the strength of the hyperfine interactions are deduced. The reduction of anisotropy in polycrystalline Ho metal is analyzed in detail, with reference to application to nuclear reaction studies using polarized nuclear targets. Spin assignments and multipole mixing ratios are deduced for the levels and transitions in ¹⁶⁶Er. [RADIOACTIVITY ¹⁶⁶Ho^m [from Ho (n,γ)] measured I_γ(θ) from oriented nuclei. ¹⁶⁶Ho^m deduced magnetic dipole moment, hyperfine interaction parameters; ¹⁶⁶Er deduced J^π, E2M1 and M2E1 mixing ratios.]