Spectral Energy Distribution Of Radiation Research Articles

Primordial plasma: influence of non-ideality on equilibrium radiation

The asymptotic behavior of the equilibrium radiation in Maxwellian plasma is investigated for the region of low frequencies. It is shown, that already for a weakly non-ideal plasma the equilibrium radiation can essentially deviate from the Planck law. The deviation from the Planck distribution is described by the transverse dielectric permittivity which takes into account both frequency and spatial dispersion. The influence of plasma non-ideality increases with increase of the non-ideality parameter in the dielectric permittivity. The spectral energy distribution of the equilibrium radiation essentially changes in the region of possibly observable frequencies. At asymptotically low frequencies there is transfer from logarithmic to power behavior of the equilibrium radiation. The results indicate that in the primordial plasma of Early Universe the spectral energy distribution of radiation could be different than the Planck one.

Simulation of positron energy spectra generated by channeling radiation of GeV electrons in a tungsten single crystal

Positron production based on the generation of channeling radiation by relativistic electrons channeled along the (110) crystallographic plane of a W crystal and the subsequent conversion of radiation into e+e--pairs in an amorphous tungsten target is described. Electron dechanneling is considered by solving of the Fokker-Planck equation. The continuous potential of the channeling plane is calculated using the Doyle-Turner approximation to the atomic scattering factor taking into account thermal vibrations of the crystal atoms. The trajectories, velocities and accelerations of planar channeled electrons are obtained by solving the classical equation of motion. In the framework of classical electrodynamics, the spectral-energy distribution of radiation is obtained from the Fourier transforms of realistic electron trajectories, velocities and accelerations within the W crystal. The calculations of channeling radiation and dechanneling are carried out by means of our Mathematica codes. The conversion of radiation into e+e−-pairs and the energy distributions of produced positrons are simulated using the GEANT4 package.

Rapid Selection of Dichroic Reflector Lamps for Color Projection

The sensitivity of the human eye to slight shifts in color balance, particularly in the blue-green and yellow-orange regions of the spectrum, necessitates careful control over all of the color-influencing parameters of a projection system. In a modern optical projection system, the dichroic coating of an integral reflector tungsten-halogen lamp may be the source of objectionable color imbalance. Despite rigorous manufacturing control, significant variations in spectral energy distribution of radiation reflected and transmitted from the dichroic coatings occur.

Beta- and Gamma-Induced Čerenkov Radiation in Water*

The spectral energy distribution of radiation from water bombarded by radium gamma-rays or P32 beta-rays is that expected for Cerenkov radiation. A solution of P32 in water furnishes a source of Cerenkov radiation which is convenient for the determination of the spectral sensitivity of photographic emulsions.