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

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2022-11, Vol.1042, p.167463, Article 167463
• Main Authors: Knafla, L., Esmaylzadeh, A., Harter, A., Jolie, J., Köster, U., Ley, M., Michelagnoli, C., Régis, J.-M.
• Format: Article
• Language: English
• Subjects: [formula omitted]–[formula omitted] angular correlations; EXILL&FATIMA; FIPPS; Gamma-ray spectroscopy; HPGe clover; ILL
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2022.167463

A new method for γ–γ 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 177Hf, 152Gd and 116Sn, populated by either β-decay or (n, γ)-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.