@article{oai:nifs-repository.repo.nii.ac.jp:00011562,
 author = {ZHAO, Mingzhong and MASUZAKI,  Suguru and MOTOJIMA,  Gen and TOKITANI,  Masayuki and YAJIMA, Miyuki and GAO, Yu and JAKUBOWSKI,  Marcin and SITJES, A. Puig and PISANO, F. and DHARD, C.P. and NAUJOKS, D. and ROMAZANOV, Juri},
 issue = {10},
 journal = {Nuclear Fusion},
 month = {Sep},
 note = {0000-0001-5089-3642, Distributions of deposits and hydrogen (H) on the graphite divertor target elements TM4h4 and TM3v5 in the test divertor units 3 (TDUs3) of Wendelstein 7-X (W7-X) are studied. The TM4h4 and TM3v5 are located at the magnetically symmetric positions in the upper and lower divertor. The microstructure of the deposition layer is characterized by a transmission electron microscope (TEM) combined with a focused ion beam (FIB). Metallic deposits such as iron (Fe), molybdenum (Mo), chromium (Cr) are detected in the deposition layer by energy-dispersive x-ray spectroscopy (EDS). The depth-resolved distribution patterns of boron (B) and metallic deposits on upper and lower horizontal (h) divertor target elements TDUs3-TM4h4 as well as upper and lower vertical (v) divertor target elements TDUs3-TM3v5 are clarified by glow discharge optical emission spectrometry (GDOES). Results for both TDUs3-TM4h4 and TDUs3-TM3v5 show that the B deposition regions exhibit higher H retention due to the co-deposition with deposits. On the other hand, up-down asymmetries in B deposition caused by particle drift exist on both TDUs3-TM4h4 and TDUs3-TM3v5. The B deposition amount on upper TDUs3-TM4h4 is 40% smaller than that on lower TDUs3-TM4h4. While for the vertical target elements, the B deposition amount on upper TDUs3-TM3v5 is 35% larger than that on lower TDUs3-TM3v5. Meanwhile, a shift of around 3 cm in B deposition peaks is observed on upper and lower TDUs3-TM4h4 and TDUs3-TM3v5. Results of numerical simulation of carbon deposition/erosion profiles on the target elements using ERO2.0 code and power flux measured by infrared cameras are shown and compared with the above mentioned B profiles.},
 title = {Distributions of deposits and hydrogen on the upper and lower TDUs3 target elements of Wendelstein 7-X},
 volume = {62},
 year = {2022}
}