The key difference between neutron capture and absorption is that neutron capture refers to the combination of a neutron and a heavy nucleus via collision whereas neutron absorption refers to the formation of a compound nucleus when a nucleus completely absorbs a neutron.
Neutron capture and neutron absorption are two types of nuclear reactions. Both these process involve the combination of a nucleus and a neutron to form a compound nucleus; however, the method of combination is different from each other. In the neutron capture process, a collision occurs whereas, in the neutron absorption process, a fission occurs.
