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.


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?

  • $\begingroup$ Is the question answerable? I mean solar pannels have limits depending on their form of collection. Gamma won't be different. But if you would say both are the same but one collects solar and the other Gamma you have your answer. They just produce energy, so they would have similar limits. Changing the wavelength doesn't change the power inside. Just how it reacts with matter. $\endgroup$ – Trioxidane Jul 22 at 21:08
  • $\begingroup$ I saw it as more of a question of whether or not there was more energy to be gathered in short wavelength radiation as opposed to visible light and whether or not there was enough short wavelength radiation in space to justify setting up such panels over conventional solar cells. $\endgroup$ – Arvex Jul 22 at 21:15
  • $\begingroup$ I think not much if Wikipedia on non atmospheric radiation tells me anything (en.m.wikipedia.org/wiki/Sunlight). Gamma isn't even on the chart. Maybe someone else can say more about it, but it seems you can get very little energy that way. $\endgroup$ – Trioxidane Jul 22 at 21:20
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    $\begingroup$ From Wikipedia: Although the Sun produces gamma rays as a result of the nuclear-fusion process, internal absorption and thermalization convert these super-high-energy photons to lower-energy photons before they reach the Sun's surface and are emitted out into space. $\endgroup$ – Trioxidane Jul 22 at 21:23
  • $\begingroup$ Are you sure those panels aren't cooling fins? Ships which generate more power must dissipate more heat. The only way for a space ship to get rid of heat is by radiating it away. The amount of heat you're capable of dissipation is proportional to your surface area. The ISS uses cooling radiators. $\endgroup$ – Luke Jul 22 at 21:35

It's not really a significant energy source. If you measure wattage carried by photons that pass through a particular volume of space, gama rays are not very significant. Visible and infrared light are the wavelength where you find the most wattage. That ratio is basically the same whether you're close to a sun or not. In deep space, far from any sun, you'll get very little energy from any form of light.

It's different if you're near a neutron star or active black hole which emit more energy in the short wavelengths. Though they still have more energy in x-rays than gama rays.

But, your gama ray absorbing panels would make excellent radiation shields.

One of the problems with gama rays is that they go through everything. Gama rays don't interact with things very often, which means they will likely go through solar panels without being absorbed. If these fictional gama panels are effective at absorbing gama rays, then they may be more valuable as shielding than as power collection.

Real world gama ray shielding involves massive blocks of lead, concrete, water, or whatever. The only way to block gama rays is to put enough stuff in front of it that it gets absorbed eventually. If you had a lighter, thinner mechanism to block gama rays that might be a big deal. Especially if your ships frequent high radiation environments or if their enemies utilize gama-ray lasers.

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  • $\begingroup$ I had intended for the ships to generate their own electromagnetic fields to deflect cosmic radiation and gamma rays similar to the magnetic field Earth has protecting it. In hindsight, that kind of hurt the idea of collecting gamma radiation from space unless I made it so they were positioned around weak points in the magnetic shielding. Easier to just leave them as conventional solar panels. $\endgroup$ – Arvex Jul 23 at 2:55
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    $\begingroup$ @Arvex That's a common misconception. Magnetic fields cannot deflect gama rays. They can't deflect any kind of electromagnetic radiation. The Earth's magnetic field only deflects charged particles. Things like Alpha and Beta radiation. The thing that protects us from cosmic rays is the atmosphere. 100km of air is a pretty good radiation shield. $\endgroup$ – Luke Jul 23 at 7:44

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