Gamma-Gamma Directional Correlations in ¹⁶⁰Dy

Abstract

The gamma-gamma directional correlation coefficients of 16 cascades in ¹⁶⁰Dy following the decay of ¹⁶⁰Tb (t_1⁄2=72.1 d) have been measured using a Ge(Li)–NaI(Tl) coincidence set-up (2τ≈6 n sec). Out of these, the correlation coefficients of the 310–962, 338–962, 392–(879)–87, 1003–(197)–87, 1103–(197)–87 and 1115–197 keV cascades have been measured for the first time. From these correlation measurements the spin value of 4⁻ has been confirmed for the 1386.5 keV level. The multipole mixing ratios of the 1003, 1103, 1115, 1200 and 1312 keV transitions in ¹⁶⁰Dy have been determined for the first time.