Ion beam analysis of W irradiated with deuterium-based plasma discharges at PF-1000U

Plasma focus devices generate discharges with dense hot plasma (HP) flows and fast ion streams (FIS) with energies up to several MeV, enabling their use to test materials for nuclear fusion applications. Tungsten plates were exposed to deuterium and to mixed deuterium-helium plasmas at distinct power flux densities at the large PF-1000U device. Elemental modifications as the induced deuterium retention and co-deposition of impurities at the target surfaces were studied by scanning electron microscopy and, particularly, by ion beam analysis (IBA). The results evidence that typically, deuterium retention is enhanced during the first discharges and may decreases afterwards due to surface erosion. Additionally, by adding helium to the working gas to generate the plasmas, deuterium retention increase. Similar results may be achieved by decreasing incident flux densities. The experiment highlights the role of the use of IBA to quantify elemental modifications imposed by irradiation of materials in plasma focus facilities.