How to accelerate neutrons?

Answer 1

Our usual particle machinery cannot accelerate neutrons and other neutral particles. However, we can create neutrons which are traveling very fast.

The best way to do this is via something called "spallation". Basically, when a high-energy proton (protons are charged, and easy to accelerate!) crashes into a nucleus, it will knock out a big spray of neutrons, protons, nuclear fragments, pions, muons, etc., all mixed together and traveling forward (in the same direction as the original proton) at high speed. (The verb "to spall" means "to split or chip; to detach small pieces")

Spallation isn't very useful unless you can sort out the neutrons from the rest of the spray. Fortunately this isn't too difficult. To sort out charged particles, pass the spallation products through a large magnetic field; charged particles will be deflected. You don't need to worry about other neutral particles (pions, lambdas, whatever) since they tend to decay within millimeters of the collision. The only thing in your "beam" a few meters away are the neutrons.

Answer 2

Neutrons can be accelerated through a process called neutron activation, typically using particle accelerators like cyclotrons or linacs to speed up the neutrons to desired energies. This involves bombarding a target material with high-energy particles, causing the target to emit neutrons as a result of nuclear reactions.