Lifetime Measurements Using RDDS Method in the Vicinity of $^{78}$Ni

Reduced quadrupole transition probabilities for low-lying transitions in neutron-rich N = 52 isotones88Kr and 86Se were investigated with a recoil distance Doppler shift (RDDS) experiment. The experiment was performed at GANIL (Caen, France) using the Orsay Universal PlungerSystem (OUPS) for the RDDS technique and the AGATAarray for the γ-ray detection coupled to the VAMOS++ magnetic spectrometer for an event-by-event particle identification. In 88Kr, the lifetimes of seven levels were determined and in 86Se, the lifetimes of five levels were determined. The deduced B(E2; 2+ 1 → 0 + 1 ) are compared with mean-field and shellmodel calculations.