Function displacement damage

Displacement damage function, 14 436 Displacement desorption, factors governing choice of method, l 614t Displacement plating, 24 141 Displacements per atom (dpa), 14 436 Displays... 

The total modified Kinchin-Pease displacement damage function is given by... 

A commonly used measure of irradiation damage is displacements per atom (dpa). A unit of 1 dpa means that on the average, every atom in the irradiated volume has been displaced once from its equiUbrium lattice site. The approximated dpa in the implanted region is given by equation 16 where 0 (ions/cm ) is the dose, and (NJE)) is the damage function given by equation 14. 

If two irradiations are undertaken in similar neutron spectra to the same total number of atomic displacements and at the same temperature, but at different rates (i.e., over different time intervals), the graphite sample with the shorter exposure time will show more damage (i.e., a flux or rate effect). This is because the net observed damage is a function not only of the total damage produced (dependant on the neutron dose), but also on the extent of annealing of that damage, which is... 

It is also quite difficult to discern if a damage in a thermoplastic is a craze or already a crack. The interferometrical measurement of the contour of a particular structure may facilitate such a decision. Figure 3,3 shows interference fringe patterns in a specimen of PC broken in a tensile test at 77 K These optical interferences originating from crack-like structures below the fracture surface have been evaluated and the square of the local displacements were plotted as a function of the distance from the surface in Fig. 3.4. According to Eq. (4) this should be a linear function in the case of a crack in contrast to a curved one for a craze (Eq. (8 b)). Thus,... 

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