Just was wondering since can't seem to find where I saw it but does anyone know what happens when a gamma ray hits a proton and a neutron?

A gamma-ray may hit a proton and it will interact via electromagnetic force. There are several possibilities:
1) Photon (gamma) gets absorbed, proton travels with a certain kinetic energy, some momentum is take by a third particle. (see Photoeffect)
2) Photon scatters: This is called Compton Effect, the gamma leaves at a certain angle with a certain energy
3)The photon is absorbed or scattered and it creates new particles (Pair creation). Photons with more then 1 MeV can create e-/e+ Pairs, higher energetic photons (200 MeV) might also create pion or myon-pairs. Energy and momentum is distributed randomly on all outgoing particles.

Low-Energy Photons cant interact with neutron, because neutron carry no charge. However high energetiv photons (several GeV) start to see the quarks inside the neutron and Quarks are carrying charge thus the same interactions are possible as in the proton case. On can excite 'hadronic' resonance (basically excited states of Quarks inside the nucleus. One can produce new pairs of Quarks, Higgs Particles (if they exist), and all kinds of other stuff. The wavelength of the gamma has to be much lower then 1fm (approx. size of the neutron).

Interaction with neutron inside a nucleus: One often reads that gamma rays interact with the whole nucleus. This is not correct. They interact only with the protons, but the protons are tightly bound to other protons and neutron by the strong force. An interaction with protons will have some instant effect on neutrons also. Thus one can say that all the particles inside the nucleus are carrying an 'effective' charge.

You mean to tell me a photon repels protons just like electrons trhough compton's effect?
Also does all following steps you mention happen to electrons as well in interaction?

This message has been edited. Last edited by: Kainchild,

As far as a photon "compton repelling" a proton, not so. You wouldn't really say that a baseball is repelled by a bat, it is conservation of momentum & energy. Because the photon loses energy (say in the X direction) the proton gets some energy in x direction.

Electrons behave exactly like protons as far as a photon is concerned (photons have no charge). Of course because pro and electrons have opposite charge, and ElectroMagnetic effects will be opposite.