Background for Context:
For the science fiction setting I am working on, I was originally intending for spaceships of a specific faction to have solar panel arrays on their larger ships. Originally, it was more as a stylistic choice to fix up some empty spaces. Some time between designing those ships and the present, I decided I wanted that faction to have exclusive access to efficient antimatter production (where the rest of humanity use fusion reactors and vent off the plasma for thrust and certain weapons.)
I got to thinking on how these solar panel arrays would be useful and decided they would be a backup power source for the electromagnetic confinement systems they store their antimatter in so that the antimattter escape if the main reactor fails.
In my research, I discovered that the energy from matter-antimatter annihilation comes in the form of gamma rays which lead me down a different line of thought. Instead of just using the gamma rays to heat water to run a steam turbine like modern nuclear fission power plants, what if the faction in question had technology that could directly absorb gamma rays and convert that energy into usable electricity? That brought me back to the solar panel arrays, wondering if such tech could be applied to them as well.
Question:
If a passive power collection system that was both functionally and visibly similar to a solar panel could absorb gamma radiation and other short wavelength radiation in space, how much could it potentially collect before hitting any thermodynamic limits?
Is there even enough energy to be found short wavelength radiation in space to justify trying to collect it as a power source? Or would it be better to leave those as dedicated solar panels and leave the short wavelength radiation-electricity conversion tech in the antimatter reactor?