Study of surface damage and hydrogen distribution in irradiated tungsten by protons in plasma focus device

Abstract

Abstracts In this paper, tungsten samples were exposed by H ions under 5, 10 and 20 PF discharges in a Mather-type plasma focus device. The hydrogen retention and the produced damage in the tungsten surface were studied. The tungsten samples were analyzed by SEM, XRD and ERDA after irradiation. The SEM micrographs showed the blisters, cracks and open bubbles on the surface of the irradiated samples. The size of the blisters increased by enhancing the number of PF discharges. The XRD pattern revealed the crack formation and propagation at the surface of the samples. The hardening and softening behavior of the exposed samples were figured out from the X-ray diffraction pattern. The ERDA was used to obtain the depth profile of hydrogen in tungsten. Ions range and the depth profile of the damage rate in the tungsten target were calculated using the SRIM code. ERDA illustrated that the highest H concentrations occurs in the target depth range of 20–60 nm whereas the SRIM simulation showed that the highest number of H ions can pierce about 60–120 nm into the tungsten sample. This discrepancy is due to the erosion. The damage rate decreases by increasing the penetrating depth.