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 

to the beam. Number of nuclei per unit volume (density of nuclei). Cross-section (microscopic cross-section). Particle flux (neutron flux). Lecture 29 

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

Effective microscopic cross sections for fissile mixtures containing In the next step, we consider radiation falling on a unit area of the xy-plane.

The microscopic cross section has units of area per interacting atom. The macroscopic cross section, which is the product of the microscopic cross section and the number of particles per unit volume, has units of inverse length. Cross sections for most reactions are determined experimentally and depend on the type of interaction, the material

Barn – The standard unit for neutron cross sections, equal to 10-24 cm2, The term cross section may refer to the microscopic cross section,.

Microscopic Versus Macroscopic Cross Section. Up to now, the cross section referred to in this article corresponds to the microscopic cross section σ.However, it is possible to define the macroscopic cross section Σ which corresponds to the total “equivalent area” of all target particles per unit volume:. where N is the atomic density of target.

cross sections into broad group macroscopic and microscopic constants. The expressed as per-unit energy in lethargy coordinates.

cross sections tallied from OpenMC worked well for small benchmark problems. [9] The isotopic cross sections generated using OpenMC (or any Monte Carlo codes that are able to generate a complete set of microscopic cross sections) with heterogeneous pin cells based on the reactor or

MICROSCOPIC REACTION CROSS SECTIONS , Each probable reaction that a neutron can undergo with a nucleus is associated with a specific cross section. The most important of them are:J, inelastic scattering cross section radiative capture cross section fission cross section (n , p) reaction cross section (n , T) reaction cross section, se si f p T D,

5 Neutron reaction cross sections •Total microscopic neutron cross section is expressed as: σ= dN/dt / [(I/A) n A ∆x] • Defining neutron flux as: φ= I/A (neutrons/sec.cm2) • Then: dN/dt = φ(A ∆x n σ) • Neutron flux can also be defined: φ= nnvn where: nn is neutron density per cm3 in beam, vn relative velocity (cm/sec.) of neutrons in beam