a) Experimentally the study of p-p scattering is capable of much higher accuracy than n-p scattering, why?
b) What are the similarities between (nn) & (pp) forces?
a) It is impossible to accelerate the neutron because neutron does not have the electrical charge. Neutrons can be produced by spontaneous fission of some transuranic element (or by several other methods), but they will have random energies. We can accelerate protons, but in this case we wouldn’t have the neutron target.
b) The nuclear force between two nucleons is charge independent. By this we mean that the strong interaction between two protons or two neutrons or a neutron and a proton is the same. (Of course, there will be different electromagnetic forces in these cases). Evidence for the charge independence of nuclear forces can be found in nucleon-nucleon scattering and in the binding energies of light mirror nuclei.