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It is known that gamma rays emitted by nuclear isomers, naturally occurring or manufactured, carry huge amounts of energy. Co-60 for example decays into the isomeric state of Ni-60 by $\beta ^-$ emission (plus the neutrino). Ni-60 then emits two $\gamma-$photons of energy $E_{\gamma_1}=1.333$ MeV and $E_{\gamma_2}=1.173$ MeV, a total of about 2.5 MeV, and attains its ground state. This amount of energy from a single decay event, is about $10^6$ times the energy in a single event in a conventional battery!

The question is: Can we utilise this amount of energy, by combining appropriate scintillators and photovoltaic cells in order to convert that energy into electrical power? Arguments for and against will be appreciated.

JKL
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2 Answers2

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Yes nuclear batteries are reasonably common, it's generally easier to just use the heat given off to drive either a stirling cycle motor or a thermo-electric generator rather than use the energy of the emitted particle directly.

They are very useful when you need power for many years without being able to recharge or replace the batteries eg. in space probes or remote monitoring sites. But they do involve large lumps of highly radioactive materials so aren't for everyone!

ps. I'm not sure what you mean by the energy of a "single event in a battery"

Martin Beckett
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  • Thank you for the reply. What about using the $\gamma$-photons directly, after perhaps first down-grading their high energy? Let us say I am interested in converting their energy using photovoltaic cells. No existing semiconductor material will do this!! As for the "single event" I was just making reference to a chemical reaction in the cell. – JKL Feb 13 '13 at 13:10
  • Typically you use beta decays and capture the electron directly to create a current. Gamma can be used together with a liquid which absorbs the gamma photon and emits light which is then detected by photoelectric device – Martin Beckett Feb 13 '13 at 23:14
  • Do you mean a liquid, or a transparent (like plastic) scintillator, so that there will be several thousands of lower energy photons available to reach the photovoltaic cell? Do you think this could be feasible for large scale electric power production? There is plenty of $\gamma$ emitting nuclear waist waiting to find some good use. – JKL Feb 15 '13 at 09:57
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Please see this article and video where a gamma ray photon brazes an atom and creates a electron positron pair. The gamma ray photon is the only one that can be caused to generate an electron positron pair under the right conditions, as lesser energy photons would not have sufficient energy.

Both the electron and the positron can then theoretically be harnessed directly for electrical power. As of this date, this is still theoretical as no such device or system has yet been demonstrated. The main difficulty is maintaining the right atom brazing conditions for the gamma rays to consistently and reliably create electron positron pairs.

0tyranny0poverty
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