Oblate collectivity in the yrast structure of Pt-194

A deep inelastic reaction using a 460 MeV Se-82 beam incident upon a thick Os-192 target was performed at the Legnaro National Laboratory, Italy. The resulting gamma-decays were measured using the GASP array. Results for Pt-194 extend the known level scheme of the yrast structure from spin I = (12 h) to (20 h). The irregularities in the sequence of the new transition energies and total Routhian surface calculations show a breakdown in collectivity with an yrast oblate shape remaining to high spin.