HIGH-SPIN GAMMA-RAY SPECTROSCOPY OF XE-122

High-spin states were populated in Xe-122(54)68 using the fusion evapo ration reaction Zr-96(Si-30,4n) at a beam energy of 135MeV. The level scheme of 122Xe has been extended up to spin approximately 30HBAR. The rotational bands and band crossings in 122Xe are assigned within the framework of the cranked shell model. Three bands are found to lose th eir rotational character or to branch above spin approximately 20HBAR. This is interpreted as the collective rotation of a prolate nucleus b eing replaced by a regime of non-collective single-particle states at high spin. Single-particle configurations are suggested for the high-s pin non-collective states using modified oscillator and Woods-Saxon po tentials. The development of the nuclear shape is analysed employing p otential energy and total Routhian surface calculations.