BLISTER FORMATION AT SUBCRITICAL DOSES IN TUNGSTEN IRRADIATED BY MeV PROTONS

Inbal Gavish Segev ^1,2 Eyal Yahel ³ Ido Silverman ² Guy Makov ¹

¹Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
²SARAF, Nuclear Research Center Soreq, Yavne, Israel
³Department of Physics, Nuclear Research Center Negev, Beer-Sheva, Israel

The material response of tungsten to irradiation by MeV protons has been studied experimentally, in particular with respect to bubble and blister formation. Tungsten samples were irradiated by 2.2 MeV protons at the Soreq Applied Research Accelerator Facility (SARAF) to doses of the order of 10¹⁷ protons/cm² which are below the reported critical threshold for blister formation derived from keV range irradiation studies. Large, well-developed blisters are observed indicating that for MeV range protons the critical threshold is at least an order of magnitude lower than the lowest value reported previously. The effects of fluence, flux, and corresponding temperature on the distribution and characteristics of the obtained blisters were studied. Focused Ion Beam (FIB) cross sections of several blisters exposed their depth and structure.