Carbon-11 decays via Positron emissions, which should be just as dangerous as beta emission (high energy electrons)….
C-11 has a half-life of about 20 minutes, but should be below background radiation in 9 hours, right?
Is there any potential to extract energy from the positron emissions? The are charged particles after all (unlike neutrons, neutrinos and gamma photons) so they could maybe be used. Or are the levels so low power they wouldn’t be much use?
