Radioactivity


course ID

Lecturer

CFU

6

Length

14 Weeks

Semester DD

First


Course details

Radioactive decay; valley of stability of nuclei; lifetime; amplitude level and the probability of decay, half-life and specific activity; branching ratio; radioactive decay: daughter activity; daughter activity in special cases; secular equilibrium. Production of radioactive sources (induced radioactivity). Decay schema of radioactive sources. The alpha decay. The nuclear radius. Energy distributions. The beta decay. Energy distribution of the beta spectrum. Properties of the neutrino. Fermi theory. Shape of the beta spectrum and the Curie plot. Selection rules of beta decay. Parity. The conservation of parity in beta decay and the experiment of Wu. The gamma-ray emission. Single transitions and transitions in cascade. Selection rules. Internal conversion. Nuclear isomerism. The fission and the fusion. The theory of Bohr and Wheeler to treat the fission process. Mechanical analogy of fission. Caloric power of fission. The chain reaction. The nuclear fusion. The origin of the elements. The standard Big Bang. Universe and primordial nucleosynthesis in stars. As a star is born . Evolution of the star. The fusion in the stele and the origin of the elements. The nuclear reactions. Energy balance: Q of the reaction. The cross section. Measurement of cross sections. Interaction of radiation with matter: the charged particles. Loss of energy by ionization. Mass density and mass stopping power. Energy loss by radiation (Bremsstrahlung). Range. Straggling and multiple straggling. Interaction of photons with matter. The Photoelectric Effect. Thomson scattering and Compton scattering. Pair production. Linear and mass attenuation coefficient. Mean free path. Emivalente layer. Coefficients absorption. Neutron interaction with matter: elastic scattering; inelastic scattering, radiative capture, reactions with emission of charged particles, reactions with emission of neutrons, fission. Attenuation of neutrons. Energy loss by the neutron in elastic scattering. The natural radioactivity and natural radiation. Natural primordial radionuclides. Other natural sources: cosmic rays. Elements on the origin of the cosmic rays; composition of the cosmic rays, secondary cosmic rays. The 14C. The Radon. Internal radioactivity in humans. Artificial radioactive sources. Elements on particle detectors. Energy resolution. Response function, response time and efficiency. Dead time. Brief description of the operation of photographic emulsions; ionization chamber; proportional counter; Geiger -Muller counter; multi -wire proportional chamber; drift chamber; TPC; organic and inorganic scintillation detectors; the photomultiplier; Cherenkov counter; semiconductor detectors; lithium drifted detectors; silicon microstrip detectors; criteria for the choice of a detector. Elements of radiation dosimetry. Main parts of the cell; somatic cells and germ cells. Biological effects of the radiation : direct effects and indirect effects. Effects on particular organs. Activity, specific activity, fluency (or flow ) of radiation, intensity fluence (or flux intensity ) of radiation, fluence (or flux) of energy, intensity fluence (or flux intensity ) energy. Exposure. The intensity of the exposure. Absorbed dose. The intensity of the absorbed dose. Relationship between exposure and absorbed dose. The kerma and the intensity of kerma . Relationship between exposure, kerma and absorbed dose in the case of photons as a function of depth in the tissue . The indicators of risk by ionizing radiation. Equivalent dose. Quality factor of radiation. The LET. Quality factor as a function of neutron energy. Effects of radiation on humans . The recommendations of the ICRP. Mention to the dedicated law. Radiation shielding. Shielding from charged particles, heavy charged particles and electrons. Shielding from photons. The build-up. Shields from neutrons. Multi- layers shields. Applications of nuclear physics: the neutron activation method and the geological and archaeological dating. Basic on measurement techniques of 14C . Other dating methods: method of 41Ca ; dating by tracks accumulation; fission-track dating. Imaging techniques.

Objectives

LEARNING OUTCOMES:
Advanced knowledge of the physics of radioactive phenomena; study of quantum theories that describe these phenomena and deepening of the experimental results related to them.

KNOWLEDGE AND UNDERSTANDING:
Students will have an very good understanding of radioactive phenomena and related research topics; the verification of knowledge and understanding will be done through oral tests.

APPLYING KNOWLEDGE AND UNDERSTANDING:
Students will be able to identify fundamentals elements of a physical problem involving radioactive phenomena and will be able to develop theoretical and analytical models to interpret these phenomena.

MAKING JUDGEMENTS:
Students will be able to realize experiment to apply the knowledge of radioactive phenomena. They will also be able to apply the acquired knowledge to perform calculations to interpret the results of the experiments. Moreover, they will have the opportunity to study