  We study pairing vibrations in $^{18,20,22}$O and $^{42,44,46}$Ca nuclei
solving the time-dependent Hartree-Fock-Bogoliubov equation in coordinate space
with spherical symmetry. We use the SLy4 Skyrme functional in the normal part
of the energy density functional and a local density dependent functional in
its pairing part. Pairing vibrations are excited by two-neutron transfer
operators. Strength distributions are obtained using the Fourier transform of
the time-dependent response of two-neutron pair-transfer observables in the
linear regime. Results are in overall agreement with quasiparticle random phase
approximation calculations for Oxygen isotopes, though differences appear when
increasing the neutron number. Both low lying pairing modes and giant pairing
vibrations (GPV) are discussed. The GPV is observed in the Oxygen but not in
the Calcium isotopes.
