What is "cross section"

cross section \cross section\ v. t. to create one or a series of cross sections[3] by cutting (an object) into thin slices.

cross section \cross section\ n.

1. a flat plane cutting through a three-dimensional object, usually at right angles to the longest axis of the object.

2. any visual representation of a cross section[1], showing the internal structure of the object in the plane of the cross section; as, the technician prepared a series of MRI cross sections of the skull.

   Note: Different cross sections created by different techniques may show different aspects of internal structure. Thus computerized axial tomography using X-rays shows different structures than are visualized by MRI.

3. a thin slice of an object made by cutting it transversely; as, to view a cross section of a bacterium with an electron microscope after staining the DNA; cross sections were prepared with a microtome.

4. a representative sample of a complex group; as, the town contained a cross section of the American population.

5. (Physics) a measure of the probability that a nucleus will interact in a specified way with a bombarding particle, expressed as the effective area that the nucleus presents to the particle; -- called also nuclear cross section.

n. 1 A section formed by a plane cutting through an object, usually at right angles to an axis. 2 (context mathematics statistics English) A sample meant to be representative of a whole population. 3 (context physics English) The probability that a particular nuclear reaction will take place.

1. n. a section created by a plane cutting a solid perpendicular to its longest axis

2. a sample meant to be representative of a whole population

3. (physics) the probability that a particular interaction (as capture or ionization) will take place between particles; measured in barns

The cross section is an effective area that quantifies the intrinsic likelihood of a scattering event when an incident beam strikes a target object, made of discrete particles. The cross section of a particle is the same as the cross section of a hard object, if the probabilities of hitting them with a ray are the same. It is typically denoted and measured in units of area.

In scattering experiments, one is often interested in knowing how likely a given event occurs. However, the rate depends strongly on experimental variables such as the density of the target material, the intensity of the beam, or the area of overlap between the beam and the target material. To control for these mundane differences, one can factor out these variables, resulting in an area-like quantity known as the cross section.

Cross section may refer to:

• Cross section (geometry), the intersection of a 3-dimensional body with a plane
• Cross-sectional views in architecture & engineering
• Radar cross section, the unit of measure of how detectable an object is with a radar
• Cross section (physics), a quantity expressing the likelihood of an interaction event between two particles
  • Absorption cross section
    • Nuclear cross section
      • Fission cross section
      • Neutron cross section
  • Emission cross section
    • Photoionisation cross section
  • Scattering cross section
• Section (fiber bundle), in differential and algebraic geometry and topology, a section of a fiber bundle or sheaf
• Cross-sectional data, in statistics, econometrics, and medical research, a data set drawn from a single point in time
• Cross-sectional study, a scientific investigation utilizing cross-sectional data
• Cross-sectional regression, a particular statistical technique for carrying out a cross-sectional study
• Cross section (geology), a diagram showing the structural geology along a vertical plane in the earth
• Cross section (biology), a sample such as that created by a microtome

In geometry and science, a cross section is the intersection of a body in three-dimensional space with a plane, or the analog in higher-dimensional space. Cutting an object into slices creates many parallel cross sections. A cross section of three-dimensional space that is parallel to two of the axes is a contour line; for example, if a plane cuts through mountains of a raised-relief map parallel to the ground, the result is a contour line in two-dimensional space showing points of equal elevation.

Cross Section is an album by American jazz pianist Billy Taylor featuring tracks recorded in 1953 and 1954 for the Prestige label. The album rereleased eight tracks from 1954 which had originally been issued on the 10-inch LP Billy Taylor Plays for DJs along with four Mambo sides from 1953.