Apparatus for in-beam hyperfine interactions and g-factor measurements: Design and operation

Abstract

The design and operation of apparatus for measurements of in-beam hyperfine interactions and nuclear excitedstate 𝑔 factors is described. This apparatus enables a magnetic field of about 0.1 tesla to be applied to the target and the target temperature to be set between ∼4 K and room temperature. Design concepts are developed mainly in terms of transient-field 𝑔-factor measurements following Coulomb excitation by the implantation perturbed angular correlation (IMPAC) technique. The formalism for perturbed angular correlations is outlined and a figure of merit for optimizing these measurements is derived to inform design. Particle detection is based on the use of silicon photodiodes of rectangular shape. The particle-𝛾 angular correlation formalism for this case is described. The experimental program to date includes temperature-dependent studies of hyperfine fields, transient-field 𝑔-factor measurements, and time-dependent perturbed angular distribution (TDPAD) studies.