Tuesday, September 30, 2014

Fall 2014: CHEM 312 Lecture 7 Fission

A general overview of nuclear fission is presented. The probability of fission is described based on developed models including the liquid drop model and shell corrections. Discussion on spontaneous fission and fissioning isomers is given. The transition nucleus and fission product distributions are discussed. The total kinetic energy, mass distribution, and charge distribution during fission are presented. Changes in fission product distribution with parent properties are introduced. Delayed neutrons from fission and their role in reactors are given. Proton induced fission is introduced. 

Sunday, September 21, 2014

Fall 2014: CHEM 312 Lecture 6 Gamma Decay

Gamma decay is described in two lectures. The first lecture covers the fundamentals of gamma decay and second lecture describes Moessbauer spectroscopy. Different methods to find data on gamma decay yields for decay of isotopes are presented. The energetics involved in gamma decay are provided. This includes recoil from gamma, which is exploited in Moessbauer spectroscopy. Decay types in gamma transitions are explained, focusing on electromagnetic basis for the gamma emission. Transition probabilities and internal conversions inherent to gamma decay are covered. Isotope examples for internal conversion electrons are given. Angular correlations in gamma decay are described with an experimental example provided. The use of gamma decay in Moessbauer spectroscopy is discussed.

Wednesday, September 17, 2014

Fall 2014: CHEM 312 Lecture 5 Beta Decay

Beta decay is presented in this lecture. The neutrino hypothesis and its relationship with beta decay is discussed. A review of Q value calculations for beta decay is provided. The importance of spin and parity, and how it can be used to assess beta decay, is discussed. Modeling beta decay through the weak force is provided.. The impact of Coulomb interactions on positron and electron spectral shape is presented. The use of Kurie plots in understanding beta decay is introduced. Selection rules in beta decay and beta transitions are explained. Calculating logft and its relation to spin and parity are presented. Double beta decay is discussed. 

Monday, September 15, 2014

Fall 2014: CHEM 312 Quiz 1

Assigned:  16 September 2014                                                   
Due: 23 September 2014                                                                             
Quiz 1 office hours:  1000-1130, 18 September 14, 1st floor HRC
Lecture 1:  Introduction, Chart of the Nuclides
Lecture 2:  Nuclear Properties
Lecture 3:  Decay Kinetics


Use lecture notes, textbooks, Chart of the Nuclides, Table of the Isotopes, and web pages.   Show your work or references on a separate page.  Please post any questions related to the quiz on the blog.

Wednesday, September 10, 2014

CHEM 312 Fall 2014: Lecture 4 Alpha Decay

This lecture discusses alpha decay in radionuclides. Theories on alpha decay are presented. Systematics and energetics involved in alpha decay are presented. The correlation between Q value and decay energy is described. The Geiger Nuttall relationship is provided, described, and utilized in a model for alpha decay. Tunneling is also exploited to described alpha decay, coupling energy and half-life. Gamow calculations are shown to reflect the Geiger Nuttall relationship. Hindered alpha decay is discussed. Hindered alpha decay is employed to described nuclear properties. Hinderance factors are described, along with how they are calculated and where they can be found. Proton and other charged particle emission are presented.

Wednesday, September 3, 2014

CHEM 312 Fall 2014: Lecture 3 Decay Kinetics

This lecture covers the fundamental equations that describe the decay of radionuclides.  Basic equations and their utility are presented.  Equations for mixtures, equilibrium, and branching of radionuclides are covered.  Examples are provided for error evaluation from counts, activity determination, evaluation of half life, and lifetime of isotopes. Discussion of natural radiation and dating are given. Examples are provided for dating from 238U, 14C, and the Oklo reactor.