How common are 2.9+MeV gamma rays in space? Could you theoretically make some form of "fusion boosted solar reactor" with something like this? Assuming not (se

How common are 2.9+MeV gamma rays in space? Could you theoretically make some form of "fusion boosted solar reactor" with something like this? Assuming not (seems like a good assumption) how low energy photons do you need to be able to use before that becomes plausible?