Which gamma radiation had more high-energy?

I am working on a short story centered around the Fukushima Daiichi nuclear disaster and I was wondering which $\gamma$ radiation had more high-energy: the radiation from the cooling water flowing through the core caused by the decay of $\rm{^{16}N}$, or the $\gamma$ emission caused by the decay of $\rm{^{137}Cs}$?


I understand that $\rm{^{137}Cs}$ has a much longer half life than$\rm{^{16}N}$ but which is the more powerful emitter of $\gamma$ rays during their respective half-lives? ([Reference Link](https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/fukushima-daiichi-accident.aspx))




There is no simple relationship between the half life of a radionuclide and the decay energy. Radioactivity only occurs when it is thermodynamically possible for a nuclear reaction to occur in the nucleous. But the nucleous must overcome a kinetic barrier for the decay to occur.


A good example of this is the alpha decay of the more heavy elements, the decay energies of Pu239 and Pu240 are almost the same but the half life of Pu240 is much shorter than that of Pu239.


Gamma emission is when nuclei which are in excited states relax into lower energy states. Normally this happens very quickly but there are examples of long lived excited states such as Ir-192m2 which has a half life of 241 years. The ground state of Ir-192 has a half life of 74 days. Thermodynamically the excited states of iridium should be able to undergo the beta decay into Pt-192. But instead the excited state of Ir-192 undergoes a internal conversion into the ground state which then does the beta decay.


 1