Global erosion and deposition patterns in JET with the ITER-like wall

Abstract

A set of Be and W tiles removed after the first ITER-like Wall campaigns (JET-ILW) from 2011-2012 has been analysed. The results indicate that the primary erosion site is in the main chamber (Be) as in previous carbon campaigns (JET-C). In particular the limiters tiles near the mid-plane are eroded probably during the limiter phases of discharges. W is found at low concentrations on all plasma-facing surfaces of the vessel indicating deposition via plasma transport initially from the W divertor and from main chamber W-coated tiles;there are also traces of Mo (used as an interlayer for these coatings). Deposited films in the inner divertor have a layered structure, and every layer is dominated by Be with some W and O content.

The 9Be(p,p0)9Be, 9Be(p,d0)8Be, and 9Be(p,α0)6Li cross-sections for analytical purposes

“…In Fig. 1a the 9 Be(p,d 0 ) 8 Be reaction peak and the 9 Be(p,p 0 ) 9 Be backscattering peak overlap with the signal from the carbon substrate, and in Fig. 1c they overlap with the Al peak.…”

“…The Au and Al peaks are well separated from the C background and from each other. The 9 Be(p,d 0 ) 8 Be reaction peak and the 9 Be(p,p 0 ) 9 Be backscattering peak can also be easily distinguished from each other. In Fig.…”

“…In fusion research it is often used for quantitative measurements of material erosion and deposition processes by analyzing wall samples from fusion devices [5][6][7][8][9]. Using EBS with incident protons makes it possible to analyze even very thick surface layers: For light elements such as Be or C layer thicknesses up to about 50 lm can be analyzed.…”

“…At higher energies the cross-section is enhanced compared to the Rutherford cross-section. Unfortunately there are only scarce data available for the 9 Be(p,p 0 ) 9 Be backscattering cross-section, which are at least twenty years old [10][11][12][13][14]. Three data sets are close to a scattering angle of 160° [11,13,14], but each covers only a limited energy range.…”

“…In this paper, cross-section data for 9 Be(p,p 0 ) 9 Be backscattering and for the 9 Be(p,d 0 ) 8 Be and 9 Be(p,a 0 ) 6 Li nuclear reactions are presented at an angle of 165°.…”