Gamma-gamma directional correlations in 90Zr

Abstract

Directional correlations of γγ cascades in 90Zr have been measured employing a twelve-channel goniometer. The obtained correlation coefficients are: 141.2–1129.1 keV, A 2 = −0.070(12), A 4 = −0.003(10); 1611.8–1129.1 keV, A 2 = −0.088(20), A 4 = 0.013(18); 1716.4–1129.1 keV, A 2 = −0.011(75), A 4 = 0.041(60); 1984.7–1129.1 keV, A 2 = −0.006(54), A 4 = −0.036(50); 827.7–1913.3 keV, A 2 = 0.164(40), A 4 = 0.062(35); 132.7–2186.4 keV, A 2 = 0.187(38), A 4 = −0.063(36); 890.6−2186.4 keV, A 2 = 0.132(51), A 4 = −0.023(48). The spin and parity 7 + is assigned to the 5060.0 keV level. The multipole mixing ratios of the involved γ-ray transitions have been determined. The γ-ray transition probabilities for some transitions are calculated and compared with predictions of the shell model for the 90Zr nucleus.