In 2023, work plan includes exposure of different types of W samples to PSI-2 plasmas (Ne, Ar, Kr) and studying erosion using laser absorption spectroscopy
Set focus on W reference layers produced within SP B.4 but start with bulk W and then proceed towards more complicated re-deposited W layers
PSI-2 geometry can be applied for all the contributing devices
Balance between erosion and re-deposition would require specific considerations
5
Discussion on joint experiments and needs for samples
Main scientific questions for cross-machine erosion experiments to be clarified
Determining absolute erosion rates? This is usually quite tricky
Study if erosion/re-deposition balance is independent of flux and only on fluence? But can this only bring forward subtle differences in machine geometries?
Investigate dependence of surface morphology on erosion/re-deposition balance? Continuation of what has been initiated on PSI-2 some years ago
Generally investigate how differently W layers mimicking re-deposits respond to plasma from that of virgin W layers? May be a bit challenging from the technical point of view in some devices
Action on AH to call for an additional meeting boiling around these questions
Involve also modellers from SP D into the loop for additional topics to be addressed
Target: April (before or after Easter)
6
Production of W samples for lab and linear-machine experiments
Be reference coatings to be produced according to a somewhat reduced work plan
Investigate influence of O (Be + O) on the structure and fuel content of the produced and annealed films --> continuation of the work initiated in 2021-2022 (incl. Raman)
Produce JET-relevant reference layers (=what we tend to see in post-exposure analyses)
Longer-term plans (2024+) could include
Tritiated Be layers and application of LIA-QMS vs. LID-QMS for investigating their fuel retention/removal trends
W layers with different morphologies, produced using TVA and short-pulse HiPIMS
8
Discussion on sample needs
Priority 1: samples for experiments in linear devices and lab conditions --> to be followed up in April-May
Priority 2: samples for LIBS experiments - but this is on hold until we know more about if and how the LIBS@JET project makes progress --> to be followed up in April-May
Action on AH to arrange a follow-up meeting in April-May once the Sample Master Excel is around and discuss on the analysis programme required for each sample
9
Erosion experiments in laboratory conditions in 2023