Nuclear reaction and heavy ion ERD analysis of wall materials from controlled fusion devices: Deuterium and nitrogen-15 studies

Time-of-flight HIERDA (26 MeV I-127(7+)) and micro-NRA (2.5 MeV He-3) were used to determine the composition of graphite and tungsten plasma-facing components (PFC) exposed at the TEXTOR and Tore Supra tokamaks. High sensitivity and resolution of HIERDA allowed, for the first time, for studies of nitrogen-15 showing that the gas injected during tokamak discharges is trapped on PFC, 3-7 x 10(15) N cm(-2). Also helium retention in tungsten has been identified: up to 8 x 10(15) He cm(-2). Deuterium distribution on the main limiters of Tore Supra is not uniform on tiles extracted from the erosion- and deposition-dominated areas. This is measured both on macro- (points 5 mm apart) and micro-scale (30 gm). The mapping with mu-NRA revealed the D content variation by a factor 40-50 in regions 1 x 2 mm(2): 1.2-40 x 10(17) D cm(-2) and 4-230 x 10(18) D cm(-2) in the erosion and deposition zones, respectively. In summary, the measurements of N-15 contributed to material mixing studies and improved understanding of deuterium retention on PFC. (C) 2011 Elsevier B.V., Published by Elsevier B.V. All rights reserved.