Meeting on results from WEST C3 marker PFUs

Friday 4 Mar 2022, 09:00 → 12:00 Europe/Berlin

https://us02web.zoom.us/j/84937716002?pwd=MUVkWThiOVovRW14Tm5BRjFqcFk2dz09

Meeting ID: 849 3771 6002
Passcode: 712197

09:00 → 09:05 Introduction

Speaker: Antti Hakola (TEKES / VTT)

09:05 → 09:15 Overview of C3 marker PFUs and sample distribution

Speakers: Dr Elodie Bernard, Dr Mathilde Diez (CEA)

introduction_CEA_March4th2022.pdf

• Background information on the two C3 marker tiles that were handed over for surface analyses
• Introduction of the s-coordinate system, distribution of core samples, and discussion on goals of this meeting
• WEMA database for sample locations, instructions to the sent to all soon, first step is "technical passport" of the samples

09:15 → 09:25 Broad-beam RBS/NRA results: overview of erosion/deposition patterns (MPG)

Speakers: Martin Balden (IPP), Matej Mayer (IPP)

2022-WPPWIE-SP-B-2a3_C3-WEST-meeting_Balden-IPP-s.pdf

• NRA and RBS analyses: standard broad beam, measurements along central line, interval 12.5 mm
• C3-34i: D, B, C, and O (indirectly) deposition profiles and W thickness changes determined (except for region with very thick deposits)
• C3-22o: generally thinner deposits and strongly erosion-dominated region
• NB! thick deposits after C4 have become even thicker --> potential issues in getting through them; in addition, peaks in terms of the s coordinates are shifted
• D largely trapped in co-deposits but also in eroded regions in small depressions (shadowed from plasma) --> calls for micro NRA

09:25 → 09:35 Broad-beam PIXE/NRA/RBS results - correspondence to MPG results (JSI)

Speakers: Mitja Kelemen (JSI), Sabina Markelj (JSI)

IJS_WEST_report_comp_IPP.pdf

• Broad beam analyses (PIXE, NRA) of selected core samples + comparison with MPG results; measurements also in the poloidal direction (=along the central line)
• PIXE allows further insights into the concentrations of trace elements (like metallic impurities)
• Relatively good agreement for NRA between IPP and JSI - except for C3-34iH (boundary region between thin and thick deposits) --> is this due to averaging over 5 successive measurement points? or delamination of the deposits partly or totally? Elzbieta and Martin says that removal locally is possible
• Also W thicknesses differ (but this may be due to DAQ at JSI) --> action on Mitja to re-check
• In addition, discrepancy of a factor of 1.5-2 between NRA data is large, should be only ~20% --> we should pay more attention to the cross-lab comparison! --> action on AH, MD, and EB to organize follow-up meetings!

09:35 → 09:45 Broad-beam PIXE/NRA/RBS results - correspondence to MPG results (IST)

Speakers: Eduardo Alves, Rodrigo Mateus (IST)

IST_WEST C3 PFUs_4March2022.pptx

• Applied the JET analysis chamber, boron quantification challenging; 4 points per sample at every 3-4 mm (and deviating from SIMS spots toroidally by ~2 mm)
• Strong deposits on C3-34iK --> consistent with MPG data --> action on Rodrigo to make a graphical comparison between MPG and IST and to determine how well they agree
• For next set of marker samples, the Mo interlayer should be thicker (~3-4 times) --> would simplify analyses and interpretation
• Cu available on some places, consistent with also microscopy analyses; stainless steel splashes visible as well --> due to arcing from SS panels (but very local phenomenon)

09:45 → 09:50 NRA results and correspondence to MPG results (NCSRD)

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

PWIE-SP B3-NCSRD-WEST-samples-Mergia.pdf

• two samples analyzed; IBA with D beam and interpretation using SIMNRA --> mainly Mo and W profiles could be extracted, agreement within ~50%
• SEM: indicates Fe and Cr, consistently with other observations; XRF: indicate their concentrations typically <0.3 at.% and generally <1 at.%
• Samples may have some additional dust on the surfaces (no special cleaning performed) but anything else is related to the features of the deposits --> one has to pay attention to inhomogeneous distribution of particles and averaging of the obtained data

09:50 → 09:55 RBS and TOF-ERDA measurements: elemental footprint and layer thickness (RBI)

Speaker: Ivancica Bogdanovic Radovic (RBI)

WEST C3_RBI.pptx

• TOF-ERDA analyses of two samples, measurements along the central line, distance between spots ~3 mm; in addition, analyses in toroidal direction --> why this time little H visible on the samples (the latter set of measurements made 8 months after the first round)? Samples stored in desiccators but not in vacuum
• Main problem: samples possibly too rough for fully reliable analyses
• He on these samples just around the detection limit --> good reference case for comparing C4 results
• Maybe escaping of H due to complex (and slow) boron chemistry? Observed F originating from the production process?
• Action to repeat measurements closer to the original measurement point to see what really has happened in the meantime

09:55 → 10:00 TOF-ERDA and NRA measurements: elemental footprint and fuel content (VR)

Speaker: Per Petersson (VR)

WEST VR.pptx

• TOF-ERDA and NRA analyses performed; NRA may have not revealed all D retained in the deposits
• Interesting to re-measure the samples but one has to keep in mind the complexities related to analyses --> then to see if similar H problems as in Iva's case arise

10:00 → 10:05 GDOES and XPS measurements: elemental footprint and layer thickness (IAP)

Speaker: Dr Eduard Grigore

GDOES and XPS measurements_IAP.pdf

• GDOES depth profiles for W, Mo, C and B extracted (integrated over a large area ~ 4 mm spot); XPS data (top surface only) available for more detailed B quantification
• Results seem to be in line with MPG data --> with the issue of the surface

10:05 → 10:10 SIMS results for elemental depth profiles (VTT)

Speaker: Antti Hakola (TEKES / VTT)

WEST_C3_analyses_SIMS_VTT.pdf

• Action to send original data (non-normalized with respect to W) to Mathilde & Elodie

10:10 → 10:15 LIBS results for elemental depth profiles (UT)

Speakers: Dr Jogi Indrek, Dr Peeter Paris

2022 March 04 WEST samples meeting_UT.pdf

• LIBS measurements performed for selected samples, ablation rate ~100 nm/shot; large noise levels for Mo and W profiles, impurities only visible for the first 3-4 shots
• Action to make SIMS/LIBS comparison and consider analysing one sample from region with thick deposits by LIBS

10:15 → 10:45 Discussion

10:45 → 10:55 SEM/EDX results for overview of surface modifications (MPG)

Speakers: Martin Balden (IPP), Matej Mayer (IPP)

• Overview of microscopy measurements given
• Thick deposits experienced delamination and peeling off; crack network visible as well
• In strongly eroded area only remnants of Mo left (erosion > 1 micron)
• Arcing also could lead to delamination, arcs burn through coating; weak arcing, in contrast, have led to no measurable depth of the arc traces and indicate deposition outside of the arc features
• Some analyses made for the side faces of tiles (=poloidal gaps)

10:55 → 11:05 SEM/EDX and FIB measurements: surface structure and microscale compositions (IPPLM)

Speaker: Elzbieta Fortuna-Zalesna (IPPLM)

• Microscopy studies of selected inner and outer divertor tiles
• No big differences observed between outer-divertor samples; no issues with marker-layer adhesion seen
• Inner-divertor samples from different characteristic regions: Mo reaches the surface in stripes on the erosion-dominated zone, flaky surfaces in the region with thick stratified deposits, Cu etc. can be seen in the deposits and not only on the surface
• Matej: quantitative information? fraction of pores in a particular deposit? What could be gained from this?
• Interesting reference case with respect to analysis of C4 samples

11:05 → 11:10 SEM/EDX and XRF measurements: surface structure and microscale compositions (NCSRD)

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

11:10 → 11:15 XRF measurements: surface structure and microscale compositions (IAP)

Speakers: Dr Eduard Grigore, Dr Ion Tiseanu

Meeting WEST_Microtomography&XRF_IAP.pdf

• XRF measurements (microtomography) of the samples sent to IAP
• W thickness evaluated (overall W thickness, not only that of the markers), comparison with SEM OK

11:15 → 11:45 Discussion

11:45 → 12:00 Final remarks and future actions

Speaker: Antti Hakola (TEKES / VTT)