[Physics] how to measure activation energy of fission

Question

i heard that fission activation energy of (235)U is less than of neutron separation energy of (236)U so this must the reason that (235)U is fission able

$$E_s+(236)U\to (235)U+n$$
in this interaction $E_s$ is neutron separation energy ( energy required to separate neutron )

1. how to measure activation energy of fission?

2. is there any relation or equation?

Answer 1

Here is a tutorial on fission .

The concept of "activation energy" is not utilized in the study of fission. There are energy levels that can be modeled with nuclear potential well models.Mass is turned into energy in fission.

What happens is that there is a high cross section for U235 to capture a thermal neutron and become a U236 in an excited state. There are more than one energy levels where this could happen.

The configuration is unstable enough that instead of falling down with gamma rays to a ground state of U236, which is fairly stable, the system (U235+neutron) breaks up into Kr92 Ba141 and 3 neutrons which can with suitable engineering be thermalized to create a chain reaction in a fission reactor.