A5064210967- Fusion materials and technologies
- Magnetic confinement fusion research
- Nuclear Materials and Properties
- Nuclear reactor physics and engineering
- Ion-surface interactions and analysis
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- Semiconductor materials and devices
- Metal and Thin Film Mechanics
- Diamond and Carbon-based Materials Research
- Laser-induced spectroscopy and plasma
- Semiconductor Quantum Structures and Devices
- Integrated Circuits and Semiconductor Failure Analysis
- Laser-Plasma Interactions and Diagnostics
- Semiconductor materials and interfaces
- Ionosphere and magnetosphere dynamics
- Metallurgical Processes and Thermodynamics
- Analytical chemistry methods development
- GaN-based semiconductor devices and materials
- Advanced materials and composites
- Plasma Diagnostics and Applications
- Advanced Materials Characterization Techniques
- Silicon and Solar Cell Technologies
- Nuclear materials and radiation effects
- High-pressure geophysics and materials
VTT Technical Research Centre of Finland
2016-2025
Culham Science Centre
2011-2024
CEA Cadarache
2013-2024
United Kingdom Atomic Energy Authority
2024
Max Planck Institute for Plasma Physics
2021
Fusion Academy
2006-2020
Fusion (United States)
2006-2020
Royal Military Academy
2020
Tekes
2005-2015
KTH Royal Institute of Technology
2006-2013
The provision of a particle and power exhaust solution which is compatible with first-wall components edge-plasma conditions key area present-day fusion research mandatory for successful operation ITER DEMO. work package plasma-facing (WP PFC) within the European programme complements laboratory experiments, i.e. in linear plasma devices, electron ion beam loading facilities, studies performed toroidally confined magnetic such as JET, ASDEX Upgrade, WEST etc. connection both groups done via...
JET is used as a test bed for ITER, to investigate beryllium migration which connects the lifetime of first-wall components under erosion with tokamak safety, in relation long-term fuel retention. The (i) limiter and (ii) divertor configurations have been studied JET-ILW (JET Be first wall W divertor), compared those former JET-C carbon-based plasma-facing (PFCs)). For configuration, gross at contact point was determined situ by spectroscopy between 4% (Ein = 35 eV) more than 100%, caused...
The N content and lattice parameter of GaNxAs1−xepilayers on GaAs (0<x<0.03) were determined by secondary ion mass spectroscopy x-ray diffraction measurements, respectively. A significant deviation the variation in GaNxAs1−x from Vegard’s law between cubic GaN was observed, which leads to overestimation nitrogen up 30% for x⩽2.5%. physical origin this negative is discussed.
ASDEX Upgrade has recently finished its transition towards an all-W divertor tokamak, by the exchange of last remaining graphite tiles to W-coated ones. The plasma start-up was performed without prior boronization. It found that large He content in plasma, resulting from DC glow discharges for conditioning, leads a confinement reduction. After change D inter-shot quickly dropped and, parallel, usual H-Mode with H factors close one achieved. initial conditioning phase, oxygen concentrations...
The issue of first wall and divertor target lifetime represents one the greatest challenges facing successful demonstration integrated tokamak burning plasma operation, even in case planned next step device, ITER, which will run at a relatively low duty cycle comparison to future fusion power plants. Material erosion by continuous or transient ion neutral impact, susbsequent transport released impurities through their deposition and/or eventual re-erosion constitute process migration. Its...
Following the first JET ITER-like wall operations a detailed in situ photographic survey of main chamber and divertor was completed. In addition, selection tiles passive diagnostics were removed from vessel made available for post mortem analysis. From results initial analysis, conclusions regarding erosion, deposition, fuel retention material transport during limiter phases have been drawn. The rate deposition on inner outer base remote corners more than an order magnitude less preceding...
Erosion and deposition were studied in the JET divertor during first ITER-like wall campaign 2011 to 2012 using marker tiles. An almost complete poloidal section consisting of tiles 0, 1, 3, 4, 6, 7, 8 was studied. The data from tile surfaces completed by analysis samples remote areas inner cladding. total mass material deposited decreased a factor 4–9 compared carbon all-carbon operation before 2010. Deposits consist mainly beryllium with 5–20 at.% oxygen, respectively, small amounts Ni,...
The First Mirror Test in Joint European Torus (JET) with the International Thermonuclear Experimental Reactor-like wall was performed polycrystalline molybdenum mirrors. Two major types of experiments were done. Using a reciprocating probe system main chamber, short-term exposure made during 0.3 h plasma operation 71 discharges. impact on reflectivity negligible. In long-term experiment lasting 19 13 X-point plasma, 20 Mo mirrors exposed, including four coated 1 μm-thick Rh layer. Optical...
Post-mortem studies with ion beam analysis, thermal desorption, and secondary mass spectrometry have been applied for investigating the long-term fuel retention in JET ITER-like wall components. The takes place via implantation co-deposition, highest values were found to correlate thickness of deposited impurity layers. From total amount retained D over half was detected divertor region. majority is on top surface inner divertor, whereas least measured main chamber mid-plane limiter....
Abstract The paper reports the first demonstration of in situ laser-induced desorption — quadrupole mass spectrometry (LID-QMS) application on a large scale fusion device performed summer 2023. LID-QMS allows direct measurements fuel inventory plasma facing components without retrieving them from device. diagnostic desorbs retained gases by heating 3 mm diameter spot wall using 1 ms long laser pulse and detects QMS. Thus, it can measure gas content at any position accessible to laser....
We have applied a low-energy positron beam and secondary ion mass spectrometry to study defects in homoepitaxial heteroepitaxial GaN layers. Positron experiments reveal high concentrations of Ga vacancies nominally undoped n-type GaN, where the conductivity is due unintentional oxygen incorporation. are observed both layers, indicating that their formation independent dislocation density. No detected p-type or semi-insulating samples doped with Mg, as predicted by theoretical energies. In Si...
We have used positron annihilation, secondary ion mass spectrometry, and photoluminescence to study the point defects in GaN grown by hydride vapor phase epitaxy (HVPE) on bulk crystals. The results show that N polar growth incorporates many more donor acceptor type impurities also Ga vacancies. Vacancy clusters with a lifetime τD=470±50ps were found near surfaces of both HVPE layers
The evaluation of hydrogenic retention in present tokamaks is crucial importance to estimate the expected tritium (T) vessel inventory ITER, limited from safety considerations 350 g. In framework European Task Force on Plasma Wall Interaction (EU TF PWI) efforts are underway investigate gas balance and fuel during discharges, compare data obtained with those post-mortem analysis in-vessel components exposed over whole experimental campaigns. This paper summarizes principal findings...
In the period 1998—2001 JET tokamak was operated with MkII Gas Box divertor. On two occasions during that a number of limiter and divertor tiles were retrieved from torus then examined ex situ surface sensitive techniques. Erosion deposition patterns determined in order to assess material erosion, migration fuel inventory on plasma facing components. Tracer techniques, e.g. injection 13C labelled methane coated low-Z high-Z marker layer, used enhance volume information transport. The results...
Mechanisms underlying the retention of fuel species in tokamaks with carbon plasma-facing components are presented, together estimates for corresponding tritium ITER. The consequential requirement new and improved schemes to reduce inventory is highlighted results ongoing studies into a range techniques removal rate ITER each case. Finally, an approach involving integration many operational schedule proposed as means extend period operations before major intervention required.
Post mortem analyses of JET ITER-Like-Wall tiles and passive diagnostics have been completed after each the first two campaigns (ILW-1 ILW-2). They show that global fuel inventory is still dominated by co-deposition; hence plasma parameters sputtering processes affecting material migration influence distribution retained fuel. In particular, differences between results from may be attributed to a greater proportion pulses run with strike points in divertor corners, having about 300...
The work presented draws on new analysis of components removed following the second JET ITER-like wall campaign 2013–14 concentrating upper inner divertor, and outer divertor corners, lifetime issues relating to tungsten coatings carbon fibre composite tiles dust/particulate generation. results show that remains region highest deposition in JET-ILW. Variations plasma configurations between first have altered material migration corners divertor. Net is shown be beneficial sense it reduces W...
Net erosion and deposition of tungsten (W) in the ASDEX Upgrade divertor were determined after 2007 campaign by using thin W marker stripes. had full-W plasma-facing components during this campaign. The inner roof baffle net areas with a maximum about 1×1018 W-atoms cm−2 private flux region below strike point. was observed whole outer divertor, largest close to Only small fraction eroded main chamber found redeposits while large either redeposited at unidentified places or has formed dust.