Author/Authors :
Hirai، نويسنده , , T. and Philipps، نويسنده , , V. and Tanabe، نويسنده , , T. and Wada، نويسنده , , M. and Huber، نويسنده , , A. and Brezinsek، نويسنده , , S. and von Seggern، نويسنده , , J. and Linke، نويسنده , , J. and Ohgo، نويسنده , , T. and Ohya، نويسنده , , K. and Wienhold، نويسنده , , P. and Pospieszczyk، نويسنده , , A. A. Sergienko، نويسنده , , G.، نويسنده ,
Abstract :
Ta–W twin limiter experiments had been carried out in TEXTOR-94. Dβ and Dγ intensities were observed during discharges. As a result, the intensities from the Ta surface were less than those from the W surface. This is attributed to the release ratio of molecules and atoms from the surface, i.e. less atomic release and more molecular release from Ta. Concerning long term D retention in Ta, D distributed uniformly over the limiter and the content was about 4×10−5 D per Ta atom. The total amount in the Ta limiter was estimated 3×1020 D in the half limiter. After exposure, the Ta bulk showed a significantly modified surface: grain growth, wrinkle like deformations and local recrystallization. However, open cracks were not observed in Ta exposed in the same condition in which W created big open crack.
