In Chadwick's experiment, alpha particle from a source are bombarded on beryllium atom and fusion occurs to produce carbon atoms. My question is that if it is that easy to cause nuclear fusion, then why do physicists need such complicated machinery to do nuclear fusion, why not just bombard with alpha particles?
Since, we can control the rate of emission of alpha particles from the source, such fusion might actually be controllable, right?
I really regret if this is a stupid question, I'm just a physics enthusiast.