A5052212156- Nuclear Materials and Properties
- Fusion materials and technologies
- Ion-surface interactions and analysis
- Microstructure and mechanical properties
- Nuclear Physics and Applications
- Nuclear materials and radiation effects
- Nuclear reactor physics and engineering
- Atomic and Molecular Physics
- Advanced Materials Characterization Techniques
- Advanced materials and composites
- Machine Learning in Materials Science
- Material Properties and Applications
- Linguistic Variation and Morphology
- Caribbean history, culture, and politics
- Nuclear and radioactivity studies
- Mass Spectrometry Techniques and Applications
- Biochemical and Molecular Research
- Graphite, nuclear technology, radiation studies
- High-pressure geophysics and materials
- RNA modifications and cancer
- Cytomegalovirus and herpesvirus research
- RNA regulation and disease
- Ion Transport and Channel Regulation
- Nuclear Issues and Defense
- Cleft Lip and Palate Research
Aalto University
2021-2024
University of Helsinki
2013-2022
Helsinki Institute of Physics
2015-2022
United Kingdom Atomic Energy Authority
2017-2019
Culham Science Centre
2017-2019
Université Paris-Saclay
2019
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2019
CEA Paris-Saclay
2019
University of Oxford
2019
Université de Lille
2019
Atomic collision processes are fundamental to numerous advanced materials technologies such as electron microscopy, semiconductor processing and nuclear power generation. Extensive experimental computer simulation studies over the past several decades provide physical basis for understanding atomic-scale occurring during primary displacement events. The current international standard quantifying this energetic particle damage, Norgett-Robinson-Torrens displacements per atom (NRT-dpa) model,...
Recent experiments on in situ high-energy self-ion irradiation of tungsten (W) show the occurrence unusual cascade damage effects resulting from single-ion impacts, shedding light nature radiation expected components a fusion reactor. In this paper, we investigate dynamics defect production 150 keV collision cascades W at atomic resolution, using molecular-dynamics simulations and comparing predictions with experimental observations. We that exhibit no subcascade break-up even high energies,...
Under the anticipated operating conditions for demonstration magnetic fusion reactors beyond ITER, structural and plasma-facing materials will be exposed to unprecedented of irradiation, heat flux, temperature. While such extreme environments remain inaccessible experimentally, computational modeling simulation can provide qualitative quantitative insights into response complement available experimental measurements with carefully validated predictions. For components as first wall divertor,...
Using in-situ transmission electron microscopy, we have directly observed nano-scale defects formed in ultra-high purity tungsten by low-dose high energy self-ion irradiation at 30K. At cryogenic temperature lattice reduced mobility, so these microscope observations offer a window on the initial, primary damage caused individual collision cascade events. Electron images provide direct evidence for power-law size distribution of high-energy cascades, with an upper limit independent incident...
At temperatures below the onset of vacancy migration, metals exposed to energetic ions develop dynamically fluctuating steady-state microstructures. Statistical properties these microstructures in asymptotic high exposure limit are not universal and vary depending on energy mass incident ions. We a model for microstructure an ion-irradiated metal under athermal conditions, where internal stress fluctuations dominate kinetics structural evolution. The balance between defect production...
Predicting strains, stresses and swelling in nuclear power plant components exposed to irradiation directly from the observed or computed defect dislocation microstructure is a fundamental problem of fusion design that has so far eluded practical solution. We develop model, free parameters not accessible direct evaluation observation, able provide estimates for irradiation-induced strains on macroscopic scale, using information about distribution radiation defects produced by high-energy...
The sizes of defect clusters, produced in materials by energetic ion or neutron impacts, are critically important input for models describing microstructural evolution irradiated materials. We propose a model the distribution vacancy and self-interstitial clusters formed high-energy impacts tungsten, provide new data from situ irradiation experiments to validate model. predicts statistics sub-cascade splitting resulting primary defects extending over entire range cluster sizes, is able...
Most experimental work on radiation damage is performed to fairly high doses, where cascade overlap effects come into play, yet atomistic simulations of the primary have mainly been in initially perfect lattice. Here, we investigate produced by energetic ion or neutron impacts bcc Fe and W. We model irradiation at fluence through cascades pre-damaged systems. The provide new insights processes governing formation under extended defects. find that leads an increase numbers large clusters Fe,...
Overlap of collision cascades with previously formed defect clusters become increasingly likely at radiation doses typical for materials in nuclear reactors. Using molecular dynamics, we systematically investigate the effects different pre-existing self-interstitial on damage produced by an overlapping cascade bcc iron and tungsten. We find that number new Frenkel pairs created direct overlap interstitial cluster is reduced to essentially zero, when size comparable disordered volume. develop...
The interaction of fusion reactor plasma with the material first wall involves a complex multitude interlinked physical and chemical effects. Hence, modern theoretical treatment it relies to large extent on multiscale modelling, i.e. using different kinds simulation approaches suitable for length time scales in connection each other. In this review article, we overview briefly physics chemistry plasma–wall interactions tokamak-like reactors, present some most commonly used relevant topic. We...
We have investigated the effect of surfaces on statistics primary radiation damage, comparing defect production in bcc metals iron (Fe) and tungsten (W). Through molecular dynamics simulations collision cascades we show that vacancy as well interstitial cluster sizes follow scaling laws both bulk thin foils these materials. The slope size distribution Fe is clearly affected by surface foil irradiation, while W mainly overall frequency affected. Furthermore, slopes power law distributions are...
It has been recently established that the size of defects created under ion irradiation follows a scaling law (Sand A. E. et al., EPL, 103 (2013) 46003; Yi X. 110 (2015) 36001). A critical constraint associated with its application to phenomena occurring over broad range conditions is limitation on energy incident particles. Incident neutrons or ions, energies exceeding certain threshold, produce complex hierarchy collision subcascade events, which impedes use defect cluster derived for an...
Two types of dislocation loops are observed in irradiated α-Fe, the 1/2〈111〉 loop and 〈100〉 loop. Atomistic simulations consistently predict that only energetically more favourable formed directly cascades, leaving formation mechanism an unsolved question. We show how can be when cascades overlap with random pre-existing primary radiation damage Fe FeCr. This indicates there no specific constraints involved loops, explain their common occurrence.
We have performed a systematic molecular dynamics investigation of the effects overlap collision cascades in tungsten with pre-existing vacancy-type defects. In particular, we focus on implications for fusion neutron irradiated relation to comparisons damage production under ion irradiation conditions. find that cascade defect decreases number new defects roughly same functional dependence as previously shown interstitial clusters. further different mechanisms govern formation dislocation...
We propose a method using solid state detectors with directional sensitivity to dark matter interactions detect low-mass weakly interacting massive particles (WIMPs) originating from galactic sources. In spite of large body literature for high-mass WIMP sensitivity, no available technique exists cover WIMPs in the mass range $<1\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. argue that single-electron-resolution semiconductor allow once properly calibrated. examine commonly used material response...
Tungsten was irradiated with different ion species (H, D, He, Si, Fe, Cu, W) at energies between 0.3 and 20.3 MeV to two calculated damage levels of 0.04 dpa 0.5 dpa.Samples were exposed a low-temperature deuterium (D) plasma 370 K decorate the radiation defects.D retention studied by nuclear reaction analysis using D( 3 p)α thermal desorption spectroscopy.For tungsten light ions He) depth profiles as well D spectra show clear differences.On other hand, medium-to high-mass (Si, identical...