CHART OF THE NUCLIDESDOE-HDBK-1019/1-93Atomic and Nuclear PhysicsNeutron-ProtonRatiosFigure 6 shows the distribution of the stable nuclides plotted on the same axes as the Chart ofthe Nuclides. As the mass numbers become higher, the ratio of neutrons to protons in thenucleus becomes larger. For helium-4 (2 protons and 2 neutrons) and oxygen-16 (8 protons and8 neutrons) this ratio is unity. For indium-115 (49 protons and 66 neutrons) the ratio of neutronsto protons has increased to 1.35, and for uranium-238 (92 protons and 146 neutrons) the neutron-to-proton ratio is 1.59. Figure 6 Neutron - Proton Plot of the Stable NuclidesIf a heavy nucleus were to split into two fragments, each fragment would form a nucleus thatwould have approximately the same neutron-to-proton ratio as the heavy nucleus. This highneutron-to-proton ratio places the fragments below and to the right of the stability curvedisplayed by Figure 6. The instability caused by this excess of neutrons is generally rectifiedby successive beta emissions, each of which converts a neutron to a proton and moves thenucleus toward a more stable neutron-to-proton ratio.NP-01Page 14Rev. 0
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
