Band Structures in $^{230}$Th

Experimental evidence for the recently proposed phenomenon of condensation of rotational-aligned octupole phonons [1] has been observed in $^{240}$Pu [2] and $^{238}$U [3]. In order to study this phenomenon in $^{230}$Th, an experiment has been carried out at ATLAS. The octupole band was extended up to spin 29. In addition, three positive-parity bands were observed for the first time. With increasing spin, the octupole band and the ground state band (gsb) start forming a smooth sequence of states with alternating spin and parity. Furthermore, the Routhian of the octupole band becomes lower than that of the gsb at rotational frequencies above 0.24 MeV. A band built on the second 0$^+$ state at 567 keV was discovered in this experiment, but it decays only to the gsb. [1] S. Frauendorf, Phys. Rev. C 77, 021304(R) (2008), [2] X. Wang et al., Phys. Rev. Lett. 102, 122501 (2009), [3] S. Zhu et al., Phys. Rev. C 81, 041306(R) (2010). This work was supported by DOE, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.