How is Thomson cross section calculated?
cross section is called the Thomson cross section, symbolized by the Greek letter sigma with subscript zero, σ0, and is equal to a numerical factor times the square of the term, electric charge squared divided by electron rest energy, or σ0 = (8π/3) (e2/mc2)2.
How do you calculate cross section scattering?
In cases where the radiation is being treated as a continuous classical wave, as in the case of long-wavelength electromagnetic radiation, scattering cross-sections are determined by dividing the power of the scattered wave by the intensity of the incident wave.
What is the differential cross section in scattering?
In other words, the differential (scattering) cross-section is defined as the ratio of the intensity of radiant energy scattered in a given direction to the incident irradiance and thus has dimensions of area per unit solid angle, dΩ.
How it is related to scattering cross section?
Scattering cross sections may be defined in nuclear, atomic, and particle physics for collisions of accelerated beams of one type of particle with targets (either stationary or moving) of a second type of particle. The probability for any given reaction to occur is in proportion to its cross section.
What is the difference between Thomson scattering and Rayleigh scattering?
Rayleigh scattering is the elastic scattering of a photon off an entire atom. Thomson scattering is the elastic scattering of a photon off a single unbound electron. Both are more likely to happen at lower energies. In particular, Rayleigh scattering cross section depends on the inverse square of initial photon energy.
How does Thomson scattering work?
When an electromagnetic wave is incident on a charged particle, the electric and magnetic components of the wave exert a Lorentz force on the particle, setting it into motion. Because the wave is periodic in time, so is the motion of the particle.
What is the formula for area of cross section?
The volume of any rectangular solid, including a cube, is the area of its base (length times width) multiplied by its height: V = l × w × h. Therefore, if a cross section is parallel to the top or bottom of the solid, the area of the cross-section is l × w.
What causes Rayleigh scattering?
Rayleigh scattering results from the electric polarizability of the particles. The oscillating electric field of a light wave acts on the charges within a particle, causing them to move at the same frequency. The particle, therefore, becomes a small radiating dipole whose radiation we see as scattered light.
What is coherent scattering?
Coherent scattering (also known as unmodified, classical or elastic scattering) is one of three forms of photon interaction which occurs when the energy of the x-ray or gamma photon is small in relation to the ionization energy of the atom. It, therefore, occurs with low energy radiation.
Who discovered Thomson scattering?
physicist J. J. Thomson
Thomson scattering is an important phenomenon in plasma physics and was first explained by the physicist J. J. Thomson.
What does the cross section for Thomson scattering illustrate?
The cross section for Thomson scattering illustrates the need for “negative energy” states in our calculations. Recall that we got the correct cross section from the non-relativistic calculation and that Thomson also got the correct result from classical E&M.
What is Thomson scattering in physics?
Thomson Scattering. When an electromagnetic wave is incident on a charged particle, the electric and magnetic components of the wave exert a Lorentz force on the particle, setting it into motion. Because the wave is periodic in time, so is the motion of the particle. Thus, the particle is accelerated and, consequently, emits radiation.
When does cross section approach that for scattering from a free electron?
If the energy of the scattered photon is much bigger than the binding energy of the atom, eV. then cross section approaches that for scattering from a free electron, Thomson Scattering. We still neglect the effect of electron recoil so we should also require that .
What is the Order of the scattering cross section?
This scattering cross section is of the order of the classical radius of the electron squared, and is independent of the frequencyof the light. The only dependence is on polarization.