  We calculate the ground-state energy of 4He, 8He, 16O, and 40Ca using the
auxiliary field diffusion Monte Carlo method in the fixed phase approximation
and the Argonne v6' interaction which includes a tensor force. Comparison of
our light nuclei results to those of Green's function Monte Carlo calculations
shows the accuracy of our method for both open and closed shell nuclei. We also
apply it to 16O and 40Ca to show that quantum Monte Carlo methods are now
applicable to larger nuclei.
