Evolution of a UCXB with a 1.3 M_⊙ NS and a 0.6 M_⊙ He star in an initial 40-minute orbit. The black line represents the standard evolution (without evaporation), and the red and green lines the evolutions with Mode A and B evaporation, respectively. The solid and dotted lines in the right panel represent the RLOF rate and evaporative mass-loss rate, respectively. The dashed magenta line denotes the critical mass transfer rate for irradiated He disks (Lasota et al. 2008).