Neutrons and Protons
Property | Neutron | Proton |
Electric charge | 0 | +1 |
Mass [kg] | 1,6750·10-27 | 1,6724·10-27 |
Mass [MeV·c2] | 939,55 | 938,28 |
Spin (angular momentum) | 1/2 | 1/2 |
Lifetime | 885,8 ± 0,9 s | >1033 years |
Magnetic dipol moment | -1,913·µk | +2,79·µk |
Parameters used by physicists to describe neutrons and protons.
Neutrons and protons carry a spin and a magnetic moment, which turns out to be different for protons and neutrons. This is a direct hint that these particles are not elementary point-like objects, but have an inner structure: they are buildup from quarks. As mentioned, neutrons as well as protons have an inner angular momentum called spin (value 1/2 h), which is an important quantum number of all elementary particles and plays an essential role for the description of matter.
Protons are electrically charged. This property enables us to accelerate protons in an electric field in an accelerator (like at CERN) and to perform collision experiments in order to study fundamental questions in physics.
When high energetic protons enter a solid body, they become strongly decelerated through the Coulomb-interaction with the atoms and molecules of matter due to the interaction of the electric charge. This property of protons is used for example in medical applications for treating eye tumors at the Helmholtz Centre Berlin (see pages Therapy of Eye Tumors).
Texts: Th. Wilpert , Ch. Schulz
