Most of you probably know a little bit about neutrons, at least in physics class.However, these small quark beams are not just filling up atomic nuclei, they are also an important part of maintaining the stability of matter.In addition, free neutrons can be used in other ways.
From breaking atoms apart by nuclear fission, to changing their composition by adding neutrons through transmutation, to using them to detect water and examine materials, neutrons are essential tools for scientific, medical and industrial applications, and that means we need better sources of neutrons.Although a large number of neutrons can be obtained through nuclear fission, simpler alternatives are needed, one of which is nuclear fusion.We will introduce neutron sources and their many applications
Bulky neutrons
Strictly speaking, neutrons, like protons, are hadrons, which means they are composite particles made of quarks with two or more valence states.Both protons and neutrons contain three quarks.The difference is that neutrons have two lower quarks and one upper quark, whereas protons have two upper quarks and one lower quark.While this sounds confusing, it is crucial to understanding the subatomic world and how it affects us.
Outside the nucleus, the neutron is unstable, with a half-life of about 10 minutes and 11 seconds before it beta-decays into a proton.A lower quark of a neutron emits a W-boson, which decayed into an electron and an antineutrino.About one thousandth of these beta decays also produce gamma radiation, a form of internal bremsstrahlung.Gamma radiation is produced when emitted beta particles (electrons) interact with (positively charged) protons.
In general, neutrons are unstable.Within the nucleus, a neutron is not necessarily stable.A nuclide (a collection of bound neutrons and protons) forms a quantum-mechanical system that may or may not form a stable energy state.In essence, neutron decay occurs if a lower energy state is available in the nuclide.An example of this is carbon-14 (6 protons, 8 neutrons), which will decay into the more stable nitrogen-14 (7 protons, 7 neutrons).
In the decay of bound neutrons we can see the same process as in the decay of free neutrons.This is different from inverse beta decay and electron capture, which allow protons in the nuclides to be converted into neutrons, which are useful to us.
Boron containing polyethylene is one of the most commonly used anti - neutron materials in neutron shielding. Because of its high strength, uniform density, acid and alkali corrosion resistance and superior neutron shielding performance, this material has been widely used in neutron shielding protection.
