Investigation of K-isomers in $^{255}$Lr and $^{256}$Rf

Recently, K-isomers have been observed in very heavy nuclei around A$\sim $250 ($^{252,254}$No). The investigation of the decay of K-isomer states in the near super heavy nuclei gives very valuable information on the ordering of single particle orbitals in these nuclei. I would like to discuss our recent results on K-isomers in $^{256}$Rf and $^{255}$Lr. The experiments were performed at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron and the decay of the isomers were studied at the focal plane of the Berkeley Gas-filled Separator (BGS). The nuclei of interest were produced via the $^{208}$Pb($^{50}$Ti, $2n)^{256}$Rf and $^{209}$Bi($^{48}$Ca, $2n)^{255}$Lr reactions.