Formal name: Cross-section Microscopy (CSM) Summary description of this technique: Cross-section Microscopy (CSM) is a technique which allows for the examination of a sample from a layered structure, such as a painted surface, at the microscopic level. The sample is typically mounted in a clear resin, which can be cut, ground, and polished to

Thus a truly microscopic derivation starting from first principles must provide firstly a formula for the empirical cross section, 

The microscopic total neutron cross-section σtotal for a specific neutron incident energy Ei can be divided into contributions from scattering, 

The Hauser-Feshbach cross section § The full formula (Hauser-Feshbach with width fluctuation): § For simplicity, we will assume W *(= 1 • Then we can sum over entrance (*) and exit (() channels separately! Sum over spin couplings in entrance channel Sum over spin couplings in exit channel Sum over energetically allowed exit channels

to perform fully microscopic cross section calculations. predictive power than extrapolations of phenomenological formulae adjusted on a very narrow 

Σ=σ.N Here σ, which has units of m 2, is the microscopic cross-section. Since the units of N (nuclei density) are nuclei/m 3, the macroscopic cross-section Σ has units of m -1. Thus, it is an incorrect name because it is not a correct unit of cross-sections.

The quantitative measure of this prediction is the cross section of the process. That is, nuclear theory is used to predict the specific cross section of a process. – This cross section may be measured in the laboratory – Comparison between theoretical prediction and measurement is used to evaluate the significance of the underlying theory.

four factor formula accurately represents the infinite multiplication factor as shown in the equation below. k∞ = ε p f η where: η = fast fission factor p = resonance escape probability f = thermal utilization factor η = reproduction factor NUCLEAR PHYSICS AND REACTOR THEORY

The atomic attenuation coefficient is also called the microscopic cross section of an atom in the absorber material. It is the microscopic “target area” sustained by an atom in the absorber. a

The quantitative measure of this prediction is the cross section of the process. That is, nuclear theory is used to predict the specific cross section of a process. - This cross section may be measured in the laboratory - Comparison between theoretical prediction and measurement is used to evaluate the significance of the underlying theory.

σ = proportionality constant in unit of area (usually barns or cm2). In this equation, σ is also known as the microscopic cross section, which is typically used