High-radiation flux

The excited-state molecules may either undergo radiationless decay to the ground state leading to the formal generation of heat under conditions of high radiation flux or radiative decay (i.e., phosphorescence), thereby emitting light. 

Nuclear reactors are a source of high radiation fluxes. 

The effect of a high radiation flux upon the structure of metal phthalo-cyanines has been investigated. Intensities of 1020 thermal neutrons/cm2 tend to convert crystalline copper phthalocyanine to an amorphous state 806). Bowden and Chadderton 86, 36), using the electron microscope, have discussed the disorder in the molecular array caused by fission damage. Tracks and dislocations due to the passage of individual fission fragments could be seen. 

Nuclear device pumped laser (NDPL) Laser pumped by the very high radiation fluxes obtainable near an exploding nuclear device. 

Most stractural adhesives will perform well when exposed to general radiation encountered in outer space over any reasonable period of time. The rigid metal-to-metal adhesives will perform satisfactorily under fairly high radiation dosages, although it is not recommended that they be exposed directiy to the space environment. The other major requirement for radiation resistance of adhesives is for nuclear reactors and related equipment with high radiation flux zones [33]. 

Ideal Performance and Cooling Requirements. Eree carriers can be excited by the thermal motion of the crystal lattice (phonons) as well as by photon absorption. These thermally excited carriers determine the magnitude of the dark current,/ and constitute a source of noise that defines the limit of the minimum radiation flux that can be detected. The dark carrier concentration is temperature dependent and decreases exponentially with reciprocal temperature at a rate that is determined by the magnitude of or E for intrinsic or extrinsic material, respectively. Therefore, usually it is necessary to operate infrared photon detectors at reduced temperatures to achieve high sensitivity. The smaller the value of E or E, the lower the temperature must be. 

The effects of the radiation flux in space on polymer materials is now of considerable importance due to the increasing use of communications satellites. Geosynchronous orbit corresponds to the second Van Allen belt of radiation, which comprises mainly electrons and protons of high energy. 

If the surface temperature does not differ greatly from the surrounding temperature, the highly nonlinear surface boundary condition may be simplified by linearizing the expression for the radiation flux and the Clausius-Clapeyron equation to yield the approximation... 

We shall employ a simplified analysis of the ablation problem utilizing the coordinate system and nomenclature shown in Fig. 12-18. The solid wall is exposed to a constant heat flux of (q/A)0 at the surface. This heat flux may result from combined convection- and radiation-energy transfer from the highspeed boundary layer. As a result of the high-heat flux the solid body melts, and a portion of the surface is removed at the ablation velocity V . We assume that a steady-state situation is attained so that the surface ablates at a constant... 

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