Spectroscopic study of beryllium plasma produced by thermionic vacuum arc

Beryllium is a candidate plasma-facing material for the main chamber wall in ITER. It will also be at JET during the ITER-Like Wall (ILW) Project aiming at tokamak operation with a full metal wall. Special marker tiles will be used in order to assess the beryllium erosion. These will be solid beryllium tiles coated first with a thin high-Z metal film (acting as an interlayer) and then with a layer of deposited beryllium. The aim of this contribution is to report on the development of a production method for thin beryllium coatings relevant for this application.