Flux effects on point defect behavior by tracking loop evolution using combined irradiation method

Irradiation flux effects are directly related to the behavior of point defects, and it is challenging to observe them experimentally. During combined irradiation, the interstitial loops produced after the first irradiation proved to be good indictors of point defect behaviors during the second irradiation with different fluxes (∼50 times of difference). For specimens without Si, the growth of pre-existing interstitial loops in the second irradiation was more distinct at lower flux, whereas the number density of nucleated defects was significantly larger at higher flux. This was attributed to the long-range diffusion of interstitials toward pre-existing sinks in the low-flux irradiation. When the flux was high, such long-range diffusion was interrupted by the rapid production of cascades and point defects. For specimens with Si, the long-range diffusion was hindered by the interstitial trapping effect of Si, which was assumed to reduce the difference between the low-flux and high-flux irradiation.