Deuterium retention in single crystal tungsten

The retention of deuterium in single crystal tungsten (SCW) has been measur ed at 300 and 500 K, as a function of incident ion fluence over the range 1 0(21)-10(24) D+/m(2). Irradiation of SCW with 1.5 keV D-3(+) ions at 300 K leads to saturation at a much lower incident fluence than seen in polycryst alline tungsten (PCW), but with the same levels of D retention at saturatio n, approximate to 5 x 10(20) D/m(2). Implantations at 500 Ii reached satura tion at a very low incident fluence, below 10(21) D+/m(2), with the amount of D retained at saturation approximate to 1.5 x 10(20) D/m(2). This level is 3-4 times lower than the saturation value for 300 Ii implantation of the same single crystal of tungsten. Deuterium depth profile analysis by secon dary ion mass spectrometry (SIMS) shows D trapping primarily within the 500 eV D+ ion implantation range for both 300 and 500 Ii profiles. SIMS also r evealed that the depth profiles for oxygen and deuterium were similar. When the tungsten was annealed at 500 K for 1 h after implantation at 500 Ii, S IMS indicated that the deuterium retention decreased by an order of magnitu de. (C) 2001 Elsevier Science B.V. All rights reserved.