>>12820541Similar to the answer before. If you change the reference frame of the beryllium atom (say, by throwing it really fast towards the x-ray source) then yes, it will emit a neutron as though it were hit by a gamma ray.
In this example it first seems like you are adding energy to the x-ray somehow, but at the end of the day, it's the energy of the system/interaction. You can look at it as a gamma ray having enough energy for the interaction or the additional energy coming from the relative momentum of the beryllium atom in a moving reference frame.
There are a couple really nit-picky things you can say about this example, but this explains the bulk of it
