اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدHigh-energy radiation damage in zirconia: modeling results
341
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Zirconia is viewed as a material of exceptional resistance to amorphization by radiation damage, and consequently proposed as a candidate to immobilize nuclear waste and serve as an inert nuclear fuel matrix. Here, we perform molecular dynamics simulations of radiation damage in zirconia in the range of 0.1-0.5 MeV energies with full account of electronic energy losses. We find that the lack of amorphizability co-exists with a large number of point defects and their clusters. These, importantly, are largely isolated from each other and therefore represent a dilute damage that does not result in the loss of long-range structural coherence and amorphization. We document the nature of these defects in detail, including their sizes, distribution and morphology, and discuss practical implications of using zirconia in intense radiation environments.
قيم البحث
اقرأ أيضاً
Understanding and predicting a materials performance in response to high-energy radiation damage, as well as designing future materials to be used in intense radiation environments, requires the knowledge of the structure, morphology and amount of ra
diation-induced structural change. We report the results of molecular dynamics simulations of high-energy radiation damage in iron in the range 0.2-0.5 MeV. We analyze and quantify the nature of collision cascades both at the global and local scale. We find that the structure of high-energy collision cascades becomes increasingly continuous as opposed to showing sub-cascade branching reported previously. At the local length scale, we find large defect clusters and novel small vacancy and interstitial clusters. These features form the basis for physical models aimed at understanding the effects of high energy radiation damage in structural materials.
Electronic effects are believed to be important in high--energy radiation damage processes where high electronic temperature is expected, yet their effects are not currently understood. Here, we perform molecular dynamics simulations of high-energy c
ollision cascades in $alpha$-iron using the coupled two-temperature molecular dynamics (2T-MD) model that incorporates both effects of electronic stopping and electron-ion interaction. We subsequently compare it with the model employing the electronic stopping only, and find several interesting novel insights. The 2T-MD results in both decreased damage production in the thermal spike and faster relaxation of the damage at short times. Notably, the 2T-MD model gives a similar amount of the final damage at longer times, which we interpret to be the result of two competing effects: smaller amount of short-time damage and shorter time available for damage recovery.
Although the effects of the electronic excitations during high-energy radiation damage processes are not currently understood, it is shown that their role in the interaction of radiation with matter is important. We perform molecular dynamics simulat
ions of high-energy collision cascades in bcc-tungsten using the coupled two-temperature molecular dynamics (2T-MD) model that incorporates both the effects of electronic stopping and electron-phonon interaction. We compare the combination of these effects on the induced damage with only the effect of electronic stopping, and conclude in several novel insights. In the 2T-MD model, the electron-phonon coupling results in less damage production in the molten region and in faster relaxation of the damage at short times. These two effects lead to significantly smaller amount of the final damage at longer times.
Radiation damage is an unavoidable process when performing structural investigations of biological macromolecules with X-ray sources. In crystallography this process can be limited through damage distribution in a crystal, while for single molecular
imaging it can be outrun by employing short intense pulses. Secondary electron generation is crucial during damage formation and we present a study in urea, as model for biomaterial. From first principles we calculate the band structure and energy loss function, and subsequently the inelastic electron cross section in urea. Using Molecular Dynamics simulations, we quantify the damage and study the magnitude and spatial extent of the electron cloud coming from an incident electron, as well as the dependence with initial energy.
We report on the effects of radiation on the light output of lead tungstate crystals. The crystals were irradiated by pure, intense high energy electron and hadron beams as well as by a mixture of hadrons, neutrons and gammas. The crystals were manuf
actured in Bogoroditsk, Apatity (both Russia), and Shanghai (China). These studies were carried out at the 70-GeV proton accelerator in Protvino.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
