Angular distributions of α particles emitted by oriented nuclei and their relation to nuclear deformation

Low-temperature spin orientation of radioactive nuclei is a nuclear spectroscopic method that allows us to obtain experimental data on nuclei and extranuclear fields. We present the results from measuring the angular anisotropy of α radiation emitted by transuranium nuclei of ^253,254Es, ²⁵⁵Fm, ^241,243Am, along with that of γ radiation from ²⁵⁰Bk nuclei oriented in an iron matrix at temperatures of 10–300 mK. The data allow us to establish the relation between the mechanism of α decay and nuclear deformation and to compare them to the theoretical data. We also measure the energy of magnetic hyperfine splitting for the investigated nuclei, and find the magnetic hyperfine field value for Es in Fe to be |B _hf | = 396(32) T. The nuclear magnetic moment for ²⁵⁴Es was determined, and its value was |μ(²⁵⁴Es)| = 4.35(41)μ _N .