ИСТИНА

Co-deposition of hydrogen isotopes with eroded beryllium is considered to be the main source of the ITER in-vessel tritium inventory. The films are expected to be localised on the surface of tungsten divertor that makes possible in situ tritium monitoring. Development of a suitable diagnostic needs the production of special samples of hydrogen rich Be coatings for testing. Such samples of 1-200 µm thick must contain hydrogen isotopes with concentration in the range from tenths to tens % [1]. An important requirement is that methods for the film production must cover various ITER scenarios from atomic deposition to micro droplet incorporation. This paper describes the films produced in experiments performed at a quasi-stationary plasma accelerator QSPA [2] where deuterium plasma flow was braked on an Al target. When moving around the target the plasma was enriched by impurities due to plasma target interaction. The plasma terminated on the chamber walls behind the target where the film deposition was found to occur. The film composition was analysed by EDS and XPS, the structure was investigated by TEM and XRD. Hydrogen content was measured by ERD while TDS was applied to study its release kinetics. The results are discussed in view of similar experiments with Be target which are in progress. [1] S. Brezinsek et al., “Beryllium migration in JET ITER-like wall plasmas”, Nucl. Fusion 55 (2015) 063021. [2] A.B. Putrik et al., “Plasma-facing material erosion products formed under ITER-like transient loads at QSPA-T plasma gun facility”, Fusion Sci. and Tech., 66 (2014) P. 70-77.