Ion Beam Studies of Deuterium Retention in High Entropy Alloys and W Targets in the PF-1000U Facility

The demands of materials proposed for nuclear fusion applications are based on high radiation hardness and low activation. Actually, W is being used as plasma facing material and High Entropy Alloys (HEAs) were proposed as thermal barriers interlayers between W and heat sink parts [2]. It is a demand to study the chemical and morphological modifications induced by plasma discharges in fusion grade materials to evaluate their behaviour under operational or accidental scenarios. In the IAEA research contract with IST under the frame of the CRP F13020 project [3], target samples with mirror quality surfaces are being irradiated in the plasma focus PF-1000 U at the IFPiLM institute in Warsaw, Poland [4], with intense deuterium plasma stream discharges. Virgin and as-irradiated samples are characterized before and after exposition by electron microscopy, namely by scanning electron microscopy (SEM) and, particularly, by ion beam analysis (IBA) at IST, Bobadela, Portugal [5], involving proton induced X-ray emission (PIXE) to investigate any possible heavy or semi-heavy elemental contamination apart the plasma species, elastic backscattering spectrometry (EBS) for other light elemental inspection, and a simultaneous Rutherford backscattering spectrometry (EBS) and nuclear reaction analysis (NRA) to quantify the retained deuterium contents from the NRA protons yields induced by the ²H(³He,p)⁴He reaction [6].