Lecture 9, Part 2: Nuclear Reactions

The second part of the nuclear reactions lecture is posted.  This section covers the mechanisms and energy ranges of nuclear reactions of interests to radiochemists.  The lecture begins with scattering reactions, moves to low energy reactions, high energy reactions, then completes with photon based interactions.  High  energy reactions include spallation products, induced fission, and compound nucleus reactions.  The lecture ends with a discussion on reactions involved in the nucleosynthesis of elements.  

Lecture 9, Part 1: Nuclear Reactions

The first part of the lecture on nuclear reactions is posted.  The lecture begins with a general definition of terms describing nuclear reactions. An example of energetics is provided using the reaction of alpha particles on nitrogen.  A description of cross sections is provided.  This includes how cross sections can be larger than the relative nucleus area.  The first lecture ends with a description of how cross sections can be experimentally measured.

Lecture 8: Nuclear Models

This lecture covers nuclear force and nuclear models.  For nuclear force, a description of the strong force, how it is attractive, and how it equally effects neutrons and protons is provided.   Charge independent force in the strong force is described with mirror nuclei.  Information on the shell model is provided, covering how it is developed and the splitting of levels.  Trends in nuclei, magic numbers, and the role of unpaired nucleons are described.  The use of the shell model to determine the spin and parity of odd A and odd-odd nuclei is given.  Examples are provided for a number of nuclei types.  The use of the Nilsson diagram to determine oblate or prolate nuclear deformation is given.  The lecture ends with a description of the Fermi gas model for excited nuclei.

Lecture 7: Fission

A general overview of nuclear fission is presented. Fission is described based the shell model, reaction energetics, and mechanisms within the nucleus. Spontaneous fission and fissioning isomers are presented. Fission product distributions are discussed, including role of energy and fissioning isotope. The total kinetic energy, mass distribution, and charge distribution during fission are presented. Delayed neutrons from fission and their role in reactors are given. Proton induced fission is introduced.

Please bring homework to the lecture on 24 October or submit by e-mail.

Test 2: Lecture 3: Decay Kinetics, Lecture 4: Alpha Decay, Lecture 5: Beta Decay, Lecture 6: Gamma Decay

The 2nd quiz is posted at http://radchem.nevada.edu/classes/chem312/quizzes.html.  The quiz will be discussed in the next class meeting on 17 October 2013. Questions related to the quiz can be posted here.  Responses to all questions will be posted on the blog.

Lecture 6: Gamma Decay

Gamma decay, the de-excitation of excited nuclei, is described in this lecture. Different methods to find data on gamma decay yields for specific isotopes are presented. The energetics involved in gamma decay are provided including recoil from gamma. 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, which exploits recoil, is discussed.

The homework question can be returned by e-mail or submitted in class on 8 October.