Multipole mixing ratios of transitions in 154Gd

#betta##betta# and esub(k)-#betta# directional correlations and the #betta# ray directional distributions from oriented nuclei have been measured to determine the multipole mixing ratios of most prominent #betta# ray transitions in 154Gd and te angular momentum change in the δπ, yes #betta# decays from 154Eu. The nuclear orientation source was prepared by implanting europium into iron and using the magnetic hyperfine interaction to produce orientation when the EuFe sample was cooled to 16 mK in a field of 0.7T. The analysis showed that the δπ, yes 3- to 2+ and 3- to 4+ transitions with log ft>10 are pure δJsub(#betta#)=1. It was found that the #betta# ray mixing ratios were approximately constant for the group of transitions linking the gamma and ground-state bands. The EO:E2 internal conversion amplitude ratio of the 873.2 keV 2+sub(#betta#) → 2+sub(GS) transition was also obtained. The value |p|=0.29+-0.01 for the EO matrix element of the 692.4 keV δI=O, δK=O transition was deduced and the ground-state deformation parameter of 154Gd, #betta#0=0.29+-0.02. Results are compared with values derived from the dynamic deformation theory based on the pairing-plus-quadrupole model and from band-mixing calculations and also with calculated values based on the interacting boson model. (author)