SP B monitoring meeting 2024

Thursday 17 Oct 2024, 13:00 → 16:00 Europe/Berlin

Join Zoom Meeting 
https://us02web.zoom.us/j/89727094589?pwd=1YTvFz4uyoROHRIGtR1iFJCjzD6aDr.1

Meeting ID: 897 2709 4589 
Passcode: 768000 

13:00 → 13:15 Overview of SP B in 2024 - summary of activities and work against deliverables

Speaker: Antti Hakola (TEKES / VTT)

SP B_Status_2024_Hakola.pptx

13:15 → 13:25 SP B.1 - Exposure of W samples to PSI-2 plasmas

Speaker: Oleksandr Marchuk (FZJ)

PSI-2_2024_Marchuk.pptx

• New high-resolution spectroscopy system available in PSI-2 and measured W spectra analysed + modelled --> paper submitted
• First B layers exposed to PSI-2 and measured spectra analysed; also B-H lines observed + O and other elements --> to be revisited!
• Comparison exercise --> previously observed high erosion rates due to Ar2+ ions, sputtering by heavy impurities and problems in estimating ion flux on the target? --> now with new exposures (and altered parameters) more reasonable erosion estimates obtained --> ready to move to next phase! (and check the data with Ne) 
• Next steps: repeat the exercise with Ne, then proceed to other W samples

13:25 → 13:35 SP B.1 - Influence of dust impacts on W coatings

Speaker: Dr Marco De Angeli (ENEA-CNR Milan)

SP B_Monitoring_Meeting_Dust_2024.pdf

• Report on the different regimes upon response to dust impacts: deformation, disintegration or dust becoming bound on the surface --> depends on the coating properties and velocity of dust particles --> also native oxide layers on (W) surfaces can change the behaviour - but no boundary effect for coatings
• New samples produced in 2024: samples with half pristine, half coated surface + further studies performed
• Next steps: impact of oblique incidence and target + dust temperature on delamination shape; effect of coating thickness on delamination?
• Open question: response of B layers to dust impacts? But is this relevant in a reactor?!

13:35 → 13:45 SP B.2 - Overview of PWI activities in W7-X

Speaker: Chandra Prakash Dhard (IPP)

WPPWIE-SPB-midterm-20241017-Dhard.pdf

• Several PWI activities done on W7-X in recent years --> overview of the efforts visible
• Dust analyses ongoing --> many elements identified; melting studies also mentioned
• Scheduling visits to W7-X --> discuss with CP

13:45 → 13:55 SP B.2 - Erosion experiments on W7-X and related surface analyses

Speaker: Matej Mayer (IPP)

SP B_Monitoring_Meeting_Mayer.pptx

• Boronization layers analysed from (i) W-coated wall tiles and (ii) MPM samples --> thickness and homogeneity determined, O gettering capacity 0.5-0.9 O/B
• 10-60 nm of B after a campaign, 5-15 nm after an individual boronization --> thin layers; how about exposure to air --> that may be an issue
• Next steps: sticking coefficient of B-H radicals? cavity samples --> challenging! comparable task on AUG!
• Also thick W7-X deposits being analyzed

13:55 → 14:05 SP B.2 - Overview of WEST tile analyses

Speaker: Dr Mathilde Diez (CEA)

DIEZ_WEST_activities_in_2024_PWIE.pptx

• Summary of the WEST PWIE activities --> see the slides for details & minutes from the Cadarache meeting in July
• New in 2024: study the effect of ripple on the erosion pattern --> to be continued also in 2025 (MPG, CEA, IAP, others?)
• New in 2024-2025: studying deposits from high-fluence campaigns --> include into analysis programme in 2025
• New in 2025: analysis of monoblock samples; Phase 1 samples cut and ready to be shipped outside of CEA
• Next steps: publications (IAEA, PFMC - He results) + which labs can analyse full tiles + monoblocks

14:05 → 14:15 SP B.3 - TOF-ERDA analyses of WEST samples

Speaker: Ivancica Bogdanovic Radovic (RBI)

PWIE monitoring meeting 2024_IBR.pdf

• Review of TOF-ERDA results --> comparison C3-C4-C5 --> most interesting comparison for He and B and W
• New in 2024: TOF-ERDA measurements of monoblock samples --> He profile extracted

14:15 → 14:25 SP B.3 - Surface analyses of WEST monoblock samples

Speaker: Konstantina Mergia (National Centre for Scientific Research “Demokritos”)

PWIE_SPB.3_Monitoring_Meeting_Demokritos_17Oct24_FINAL.pdf

• Summary of results obtained from MB28 - deposits and fuel retention profiles + overview of morphology
• Lower retention compared to the marker tiles --> reasons for this?
• Discussion on "humps" --> also seen on other machines
• Next steps: publishing the results

14:25 → 14:35 SP B.4 - production of W reference samples

Speaker: Prof. David Dellasega (ENEA)

Dellasega_ deposition_MM24_def2.pdf

• Review of W films produced in 2024 - for LIBS campaigns and linear-machine experiments
• New in 2024: nanocolumnar W films (crystalline rods) --> first attempts resulted in tilted rods while the Madrid teams had a different outcome --> largely dependent on critical parameters 

14:35 → 14:45 SP B.4 - production, characterization, and exposure of B reference samples

Speaker: Anne Houben (FZJ)

SP_B_1024_ahouben.pdf

• B layers produced and characterized (magnetron sputtering) --> B layers appear to detach from their W substrate (due to W oxide?) --> best to anneal W substrates before deposition and keep in vacuum (similar effect on steel but only after several months --> humidity effect)
• B erosion in PSI-2 --> erosion rates 0.26-0.43 nm/s (PSI-2 beam profile), quite consistent for long-term and short-term exposures (rate can increase up to 0.6 nm/s) - these obtained by spectroscopy!
• Next steps: comparison to layers produced by other groups
• Possible follow-up exercise: chemical erosion of B layers? Sabina can study this

14:45 → 14:55 SP B.4 - production and characterization of B reference samples

Speaker: Eduardo Pitthan Filho (VR)

SPB_Pitthan_2024_indico.pdf

• B films produced by magnetron sputtering on W substrates --> layers appear to be stable but they can change color upon exposure to air (in minutes)
• Collection of data from W-B mixed layers and pure B coatings; proposal to carry out in situ experiments on H/D desorption
• NB! aging effect considerable (formation of boric acid)
• Detailed analysis of the layers carried out, combining multiple IBA techniques recommended --> new methods available for B detection
• Next steps: participate in the comparison exercise proposed by Anne

14:55 → 15:10 SP B.5 - Production of B and W dust particles

Speakers: Dr Corneliu Porosnicu (IAP), Tomy Acsente (IAP)

2 Reporting slides 2024 activities IAP - Bobi.pdf

SPB5 Monit meet oct 2024 W_B MSGA A Tomy.pdf

• W dust particles: clear impact of deposition rate, D retention etc. by addition of water vapor on the production of nanoparticles; particles also become more "disconnected"
• B dust particles: produced using both magnetron sputtering (nanoparticles) and plasma arcing (big clusters) --> inclusion of H, N, and O changes the properties of dust particles + some notable differences compared to W dust
• Next step: comparing lab dust to dust coming from fusion devices + finishing the database

15:10 → 15:30 Discussion

15:30 → 15:35 Final remarks and actions

Speaker: Antti Hakola (TEKES / VTT)