Как выбрать гостиницу для кошек
14 декабря, 2021
Сегодня каждый, кто собирается в отпуск и не знает, с кем оставить своего котика или кошку, может во[...]
Very low temperature regime: immobile SIAs (T
At very low temperatures where defect migration does not occur, defect accumulation is typically proportional to dose until the defect concentration approaches the level where defects created in displacement events begin to overlap and annihilate preexisting defects created earlier in the irradiation
exposure. The defect accumulation kinetics73 can be described by N = Nmax[1 — exp(—Aft)], where the parameter A is determined by the spontaneous recombination volume for point defects or the cascade overlap annihilation volume for defect clusters and ft is the product of the irradiation flux and time. Due to the lack of defect mobility, defect clusters resolvable by TEM are usually not visible in this irradiation temperature regime unless they are created directly in displacement cascades by energetic PKAs.74 Saturation in the defect concentration typically occurs after ^0.1 dpa as monitored by atomic disorder,75-77 electrical resistivity,78-82 and dimensional change.83-85 Due to the large increase in free energy associated with lattice disordering and defect accumulation, amorphization typically occurs
in this temperature regime in many ceramics and ordered metallic alloys87,88 for doses above ~0.1- 0.5 dpa. Figure 7 shows an example of the dose — dependent defect concentration in ion-irradiated ZnO at 15 K as determined by Rutherford backscat-
tering spectrometry.
At very low temperatures where defect migration does not occur, defect accumulation is typically proportional to dose until the defect concentration approaches the level where defects created in displacement events begin to overlap and annihilate preexisting defects created earlier in the irradiation
exposure. The defect accumulation kinetics73 can be described by N = Nmax[1 — exp(—Aft)], where the parameter A is determined by the spontaneous recombination volume for point defects or the cascade overlap annihilation volume for defect clusters and ft is the product of the irradiation flux and time. Due to the lack of defect mobility, defect clusters resolvable by TEM are usually not visible in this irradiation temperature regime unless they are created directly in displacement cascades by energetic PKAs.74 Saturation in the defect concentration typically occurs after ^0.1 dpa as monitored by atomic disorder,75-77 electrical resistivity,78-82 and dimensional change.83-85 Due to the large increase in free energy associated with lattice disordering and defect accumulation, amorphization typically occurs
in this temperature regime in many ceramics and ordered metallic alloys87,88 for doses above ~0.1- 0.5 dpa. Figure 7 shows an example of the dose — dependent defect concentration in ion-irradiated ZnO at 15 K as determined by Rutherford backscat-
tering spectrometry.