Development of a new γ-γ angular correlation analysis method using a symmetric ring of clover detectors

A new method for gamma-gamma angular correlation analysis using a symmetric ring of HPGe clover detectors is presented. Pairwise combinations of individual crystals are grouped based on the geometric properties of the spectrometer, constrained by a single variable parameterization based on symmetry considerations. The corresponding effective interaction angles between crystal pairs, as well as the attenuation coefficients are extracted directly from the measured experimental data. Angular correlation coefficients, parameter uncertainties and parameter co-variances are derived using a Monte-Carlo approach, considering all sources of statistical uncertainty. The general applicability of this approach is demonstrated by reproducing known multipole mixing ratios in Hf-177, Gd-152 and Sn-116, populated by either beta-decay or (n,gamma)-reactions, measured at the Institut Laue-Langevin, using the EXILL&FATIMA spectrometer and different configurations of the FIPPS instrument. The derived mixing ratios are in excellent agreement with adopted literature values with comparable or better precision.

Automated summary

This article presents a new method for gamma-gamma angular correlation analysis using a symmetric ring of HPGe clover detectors. It demonstrates the effectiveness of this method by reproducing known multipole mixing ratios in various isotopes with high precision and accuracy.