Measurement of Reduced Electromagnetic Transition (BM1/BE2) in the Strongly Coupled Bands in 161Er Nuclei

In this study, we examined the ratios of reduced electromagnetic transition probabilities for strongly coupled bands in 161Er nuclei using the Gammasphere spectrometer. The nuclei were populated via the 116Cd (48Ca, 3γ) fusion-evaporation reaction at a beam energy of 215 MeV. Experimental B(M1)/B(E2) ratios were extracted from the coincidence spectra using the Radware software suite. These results were compared with theoretical calculations to investigate the evolution of magnetic dipole and electric quadrupole transition strengths within the coupled bands. The observed B(M1)/B(E2) ratios are consistent with systematic trends in neighbouring isotopes; however, they exhibit a reduced M1 strength, particularly at low spin, as the nucleon number increases. The observed decrease indicates a reduction in the magnetic dipole component associated with changes in the underlying quasiparticle configuration. The experimental results closely match theoretical predictions, thereby validating the proposed configurations and expanding the systematics of B(M1)/B(E2) ratios within the Er isotopic chain.