Imaging of tritium implanted into graphite

The extensive use of graphite in plasma-facing surfaces of tokamaks such as the Tokamak Fusion Test Reactor, which has planned tritium discharges, makes two-dimensional tritium detection techniques important in helping to determine torus tritium inventories. We have performed experiments in which highly oriented pyrolytic graphite (HOPG) samples were first tritium implanted with fluences of ∼1016 T/cm2 at energies approx. <25 eV and then the near-surface implant distributions were detected in two dimensions using tritium imaging. A portion of the sample was masked off during the implant in order to produce a well-defined implant boundary. Heating of the HOPG samples to temperatures as high as 500 0C resulted in no discernible motion of tritium along the basal plane, but did show that significant desorption of the implanted tritium occurred. The current results indicate that tritium in quantities of 1012 T/cm2 in tritiated components could be readily detected by imaging at lower magnifications