The latest technology being deployed at ports uses pressurized natural helium to directly detect fast neutrons, without the need for bulky neutron moderators. Utilizing recoil nuclei following neutron scatter events, natural helium glows (scintillates), allowing photomultipliers (e.g. SiPMs) to produce an electrical signal. Introducing moderators and lithium-6 to capture thermalized neutrons further increases the detection capabilities of natural helium, at the expense of losing the initial information of the neutrons (such as energy) and reducing sensitivity to shielded neutron-emitting materials.