Beta and Gamma-decays of nuclei
Gorozhankin
Abstract
The main task of this course is to extend the knowledge about basic regularities of radioactive decay, which students have received during their study for bachelor’s degree, and to give students insight into experimental methods, used for measuring characteristics of nuclei. The course is devoted to experimental nuclear physics, in which we thoroughly analyse theoretical and practical basics of the majority of the methods, used today for the determination of characteristics of radiation, emitted in the process of radioactive decay, and questions, connected with the proper management with and interpretation of measurement results.
The aim of the study
To study basic regularities of mostly widespread types of radioactive nuclear fission and basic nuclear properties, to describe types of nuclear transformation, techniques of the study of nuclear decay and methods for the determination of basic nuclear characteristics.
Having done this course, a student should acquire knowledge about modern techniques of nuclear spectroscopy, gain insight into calibration/graduation (градуировка) and execution of measurements with the use of different types of detectors and spectrometers.
The contents of the discipline
1.Alpha-decay. Abundance of alpha-decay nuclei. Energy of alpha-decay. Geiger-Nuttall rule. One-particle alpha-decay theory (by Gamow). Systematics of alpha-transitions, selection rules in alpha-decay.
Beta-decay. Types of beta-transitions in nuclei and energy (энергетика) of beta-decay. Fermi theory. Beta-transition probabilities. Саржентrule. Classification of beta-transitions in degree of forbiddenness, reduced probabilities log (ft), selection rules. Allowed beta-spectrum shape. Influence of nuclear Coulombian field. The shape of unique and nonunique forbidden beta-spectra. Space parity violation/nonconservation (несохранение) in beta-decay.
Gamma-decay. Electric and magnetic multipole radiation. One-particle units of Weisskopf, Moshkovskii. Reduced probabilities of electromagnetic transition in nuclei. Internal conversion of gamma-rays. Coefficients of internal conversion and their dependence on multipolarity of radiation.
Exotic types of decay. Single- and double-proton and –neutron decays. Delayed proton and neutron decays. Cluster radioactivity. Double beta-decay. Inverse beta-decay. Beta-decay in the localized state. (в связанном состоянии).
2. Alpha-emission. Beta-emission. Gamma-emission. Gamma-ray internal conversion.
3. X-ray radiation. Auger electrons. Internal and external deceleration radiation (тормозноеизлучение).
4. Interaction of heavy charged particles with matter. Interaction of electrons with matter. Interaction of electromagnetic emission with matter.
5. Methods of radiation detection. Radiation detector. Spectrometer response function.
Spectrometry of heavy charged particles. Magnetic spectrometers. Ionisation methods.
Spectrometry of electrons. Magnetic spectrometers. Electrostatic spectrometers. Spectrometer with semiconductor detectors.
Spectrometry of gamma-rays. Scintillation spectrometers.Wave dispersion spectrometers.Spectrometer with semiconductor detectors. Instrumental (Аппаратурный)spectrum. Effects, which deform instrumental (аппаратурный) spectrum. Instrumental spectra processing. Calibration of spectrometers.
6. Measurement of parity violation/nonconservation during beta-decay (Woo’s experiment). Measurement of neutrino helicity (Goldhaber’s experiment). Measuring of two-neutrino double beta decay (experiments by S.R. Elliott, NEMO).
3.3 Methodical recommendations for the tutor
The aim of this course is to extend the knowledge of students about types, properties and regularities of radiation, emitted in the radioactive nuclear decay, and about experimental methods for the determination of basic characteristics of radiation and nuclei. While describing different methods for detection of charged particles and electromagnetic emission, we focus on their spectrometry, i.e. determination of basic properties of emissions, which is based on the analysis of their spectral composition.
The course includes parts of modern spectrometry of emissions, which are most frequently used in different experiments. Concluding lectures offer students an opportunity to get a detailed acquaintance with setting and implementation of several experiments, which are regarded as classical today.