1. Nuclear Physics I Dr. Mohammed Hassen Abu-Sei’leek

2. CH 1: Basic Concepts In 1896, Henri Becqurel discovered that radiation from uranium salt cast shadows of opaque objects which could be recorded on a photographic plates wrapped in black papers. ( this radiation is persisted even when the excited light had been removed) ≡ radioactivity.

3. Radiations have the ability to discharge an electrified body by using of the current in an ionization chamber for quantitative measurements. In 1898, Piece and Mary Curie separate plutonium and radium from crude U ores. Bequeral’s work attracted Ernest Rutherford who studied the conductivity of gases under J. Thomson in Cambridge investigated the radiation of Thorium.

5. Rutherford, Soddy and Monterial found Radioactivity produced new chemical substances. Some Introductory Terminology: 1.Z is atomic number gives number of protons (p). In neutral atoms have Z protons & Z electrons. 2.A is mass number of a nucleus. A=Z+N where N is number of neutrons Proton and neutron are form a family of nucleons.

6. Nuclides A nuclide is a specific combination of a number of protons and neutrons. is the complete symbol for a nuclide, but the information is redundant and is sufficient. X is the chemical symbol of the element. Nuclides with the same atomic number Z are called isotopes, same A isobars, same N isotones (isos (gr.) - the same).

7. We generally use the form Isotopes are nuclei with Z proton that can have a variety of different mass number Isotones are nuclei with the same N but different Z such as: Isobars are nuclei with the same A such as: Any nucleus contains Z protons & N neutrons. The present of electrons within the nucleus is unsatisfactory for several reasons:

8. 1.The nuclear electrons would need to be bound to the protons by a very strong force, stronger even than the Coulomb force. Yet no evidence for this strong force exists between protons and atomic electrons. 2.To confine electrons in a region of a nucleus,by using the uncertainty principle, these electron have a momentum with a range.Electrons that are emitted from the nucleus in radioactive β decays have energies ˂ 1 MeV; never do we see decay electron with 20 MeV energies.

9. 3.The total intrinsic angular momentum (spin) of nuclei for which A-Z is odd would disagree with observed value if A protons and A-Z electrons were present in the nucleus. For example, according to p-e hypothesis would contain 2 p and 1e. but the observed spin of the deuterium nucleus is 1. 4. Nuclei containing unpaired electrons would be expected to have magnetic dipole moments far greater than those observed.

10. For example -nucleus, if a single electron was present in a -nucleus, we would expected the nucleus to have a magnetic dipole moment about the same size as that of an electron, but the observed magnetic moment of the deuterium nucleus is about 1/2000 of the electron’s magnetic moment. Neutron was discovered by Chadwick in 1932. Atomic mass unit,