Science Experiment

Actually, not so much an experiment, but a question.  The question occurred to me as I was perusing the subject of antimatter.  In particular, the use of antimatter for rocket propulsion.  This search didn't yield much in the way of answers, but it did yield one question.  The question was this: What would happen if an electron collide with a proton?  The link provided was an answer to the question somebody else had a couple years ago.  So, I'm not the only one who came up with that one.  The best answer, derived from the link, was that energy was formed.  But this energy is vaguely specified in the answer, so I am not completely satisfied by it.  Energy in the form of photons?  How much?  Is it usable for some purpose?  In particular, can it be harnessed to produce something useful?

Actually, the question literally asks what happens when electrons and protons collide.  But since a positron is the antimatter equivalent of an electron, one wonders what the outcome would be.  The positron question is the second part of the question, now I see.  The ask a scientist source didn't refer to the antimatter part of the question.

I was wondering because positrons can be formed in substantial number ( at least it is substantial compared to  the formation of positively charged ions of antimatter ).  What if you could use this fact in order to produce something useful?  That is, produce positrons that would in turn produce something useful, like gobs and gobs of energy.

I found out that the collision of an electron and positron makes gamma ray photons.  Gamma rays might be usable, but it wouldn't be easy nor practical for space propulsion.  If the collision of a proton and positron formed photons and neutrinos only, could this be used for something?  Neutrinos aren't useful.  The can pass through the Earth and not be noticed.  They are like ghost particles.  Photons are light particles, but in what wavelength and so forth?

Further searching yielded this pdf file.  Not exactly an answer, but it did appear to confirm what I thought.  The electric charges were attracting in some way.  The pdf file appears to be about separating the particles.  Evidently, they don't annihilate each other.  ( I think)