Analysis of deposited layers with deuterium and impurity elements on samples from the divertor of JET with ITER-like wall

Inconel-600 blocks and stainless steel covers for quartz microbalance crystals from remote corners in the JET-ILW divertor were studied with time-of-flight elastic recoil detection analysis and nuclear reaction analysis to obtain information about the areal densities and depth profiles of elements present in deposited material layers. Surface morphology and the composition of dust particles were examined with scanning electron microscopy and energy-dispersive X-ray spectroscopy. The analysed components were present in JET during three ITER-like wall campaigns between 2010 and 2017. Deposited layers had a stratified structure, primarily made up of beryllium, carbon and oxygen with varying atomic fractions of deuterium, up to more than 20%. The range of carbon transport from the ribs of the divertor carrier was limited to a few centimeters, and carbon/deuterium co-deposition was indicated on the Inconel blocks. High atomic fractions of deuterium were also found in almost carbon-free layers on the quartz microbalance covers. Layer thicknesses up to more than 1 μm were indicated, but typical values were on the order of a few hundred nm. Chromium, iron and nickel fractions were less than or around 1% at layer surfaces while increasing close to the layer-substrate interface. The tungsten fraction depended on the proximity of the plasma strike point to the divertor corners. Particles of tungsten, molybdenum and copper with sizes less than or around 1 μm were found. Nitrogen, argon and neon were present after plasma edge cooling and disruption mitigation. Oxygen-18 was found on component surfaces after injection, indicating in-vessel oxidation. Compensation of elastic recoil detection data for detection efficiency and ion-induced release of deuterium during the measurement gave quantitative agreement with nuclear reaction analysis, which strengthens the validity of the results

Studies of dust from JET with the ITER-Like Wall: Composition and internal structure

Results are presented for the dust survey performed at JET after the second experimental campaign with the ITER-Like Wall: 2013–2014. Samples were collected on adhesive stickers from several different positions in the divertor both on the tiles and on the divertor carrier. Brittle dust-forming deposits on test mirrors from the inner divertor wall were also studied. Comprehensive characterization accomplished by a wide range of high-resolution microscopy techniques, including focused ion beam, has led to the identification of several classes of particles: (i) beryllium flakes originating either from the Be coatings from the inner wall cladding or Be-rich mixed co-deposits resulting from material migration; (ii) beryllium droplets and splashes; (iii) tungsten and nickel-rich (from Inconel) droplets; (iv) mixed material layers with a various content of small (8–200nm) W-Mo and Ni-based debris. A significant content of nitrogen from plasma edge cooling has been identified in all types of co-deposits. A comparison between particles collected after the first and second experimental campaign is also presented and discussed. Keywords: Dust, JET, ITER-Like Wall, Beryllium, Tungsten, Material mixin

Tracer techniques for the assessment of material migration and surface modification of plasma-facing components

Tracer techniques were used in the TEXTOR tokamak to determine high-Z metal migration and the deposition of species used for plasma edge cooling or wall conditioning under different types of operation conditions. Volatile molybdenum hexa-fluoride, nitrogen-15 and oxygen-18 were used as markers in tokamak or ion cyclotron wall conditioning discharges (ICWC). The objective was to obtain qualitative and quantitative of a global and local deposition pattern and material mixing effects. The deposition and retention was studied on plasma-facing components, collector probes and test limiters. Optical spectroscopy and ex-situ analysis techniques were used to determine the plasma response to tracer injection and the modification of surface composition. Molybdenum and light isotopes were detected on all types of limiters and short-term probes retrieved from the vessel showing that both helium and nitrogen are trapped following wall conditioning and edge cooling. Only small amounts below 1 × 1019 m−2 of 18O were detected on surfaces treated by oxygen-assisted ICWC

MATLAS project - Advanced methods of materials engineering in diagnostics of art works after renovation by means of shaped, high-energy laser radiation pulses

Projekt MATLAS PL0259, realizowany w ramach Mechanizmu Finansowego EOG/Norweskiego Mechanizmu Finansowego, w Obszarze Priorytetowym "Konserwacja Europejskiego Dziedzictwa Kultury", został z powodzeniem rozpoczęty w lipcu 2008 r. Naukowe cele projektu obejmują opracowanie metod diagnostyki powierzchni dzieł sztuki wykonanych z metali (stopów) w celu ich bezpiecznej renowacji laserowej, opracowanie systemu laserowego zdolnego do generacji impulsów o wymaganym w renowacji, kontrolowanym kształcie i czasie trwania oraz analizy zjawisk indukowanych przez impulsy laserowe na powierzchni obiektów historycznych. Artykuł przedstawia uczestniczące w projekcie ośrodki naukowe, projekt i wykonanie laserowego systemu czyszczącego oraz metodykę badań eksperymentalnych. Podsumowuje on również najnowsze wyniki projektu oraz przedstawia metalowe dzieła sztuki wybrane do badań, wraz z ich analizami historycznymi i strukturalnymi.MATLAS project PL0259 successfully started in July 2008 under the EEA Financial Mechanism/ Norwegian Financial Mechanism and in the Key Priority Section "Conservation of European Cultural Heritage". The scientific aims of the project include: development of diagnostic methods for analysis of metal (alloy) artworks surfaces for safe laser renovation; development of a laser system capable of generating pulses with controlled shape and time duration required for renovation, and analysis of phenomena induced by laser pulses in the treated surfaces of historical objects. The paper presents participating scientific teams, design and realization of laser cleaning system and methodology of experimental investigations. It also summarizes the latest project results and presents metal artworks selected for examination with their historical and structural analysis

Dust Generation in Tokamaks: Overview of Beryllium and Tungsten Dust Studies in JET with the ITER-Like Wall

Operation of the JET tokamak with beryllium and tungsten ITER-like wall provides unique opportunity for detailed studies on dust generation: quantity, morphology, location, etc. The programme carried out in response to ITER needs for safety assessment comprises: (i) remotely controlled vacuum cleaning of the divertor; (ii) local sampling of loosely bound matter from plasma-facing components (PFC); (iii) collection of mobilized dust onvarious erosion-deposition probes located in the divertor and in the main chamber. Results of comprehensive analyses performed by a number of complementary techniques, e.g. a range of microscopy methods, electron and ion spectroscopy, liquid scintillography and thermal desorption, are summarized by following points: (a) Total amount of dust collected by vacuum cleaning after three campaigns is about 1–1.4 g per campaign (19.1–23.5 h plasma operation), i.e. over 100 times smaller than in JET operated with carbon walls (i.e. in JETC). (b) Two major categories of Be dust are identified: flakes of co-deposits formed on PFC and droplets (2–10 μm in diameter). Small quantifies, below 1 g, of Be droplets and splashes are associated mainly with melting of beryllium limiters. (c) Tungsten dust occurs mainly as partly molten flakes originating from the W-coated tiles.The 13the International Symposium on Fusion Nuclear Technology(ISFNT-13