High-K structure in Fm-250 and the deformed shell gaps at N=152 and Z=100

The structure of high-spin and nonyrast states of the transfermium nucleus {sup 250}Fm has been studied in detail. The isomeric nature of a two-quasiparticle excitation has been exploited in order to obtain spectroscopic data of exceptional quality. The data allow the configuration of an isomer first discovered over 30 years ago to be deduced, and provide an unambiguous determination of the location of neutron single-particle states in a very heavy nucleus. A comparison to the known two-quasiparticle structure of {sup 254,252}No confirms the existence of the deformed shell gaps at N=152 and Z=100.