Could a particle(proton, gold ion, electron) beam reach the surface of the moon, given current technology? Would the beam diffuse too much too scenter the regolith? Or would the beam have to be focused or continually refocused in order to achieve that? If so why can they do it with laser (photon beams) into a reflector but not be able to focus a particle beam from earth onto the lunar surface? Thank you for any insight.