Investigations of adsorption states of protium and deuterium in redeposited carbon flakes formed in tokamak T-10

Abstract

This work reports thermal desorption spectroscopy (TDS), Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) analyses on free standing redeposited hydrocarbon films (flakes) with a high deuterium to hydrogen isotopic ratio, produced in the T-10 tokamak in the Kurchatov Institute. XRD pattern showed that the carbon flakes differ substantially from graphite and are non-crystalline. The TDS D2(H2) curves consist of two groups of peaks (450-800 K and 900-1000 K), and appeared to be rather similar to those obtained for a mechanically milled nanostructured graphite. As a result, two main adsorption states with activation energies of about 0.65 and 1.25 eV/H were found, implying a hopping diffusion and a resonance mechanism, respectively. The IR spectral differences between reddish-gold and dark-brown flakes showed a less degree of C-H hybridization for dark films and a disordered carbon network, to which the CD2,3 end-groups are connected. © 2008 Elsevier B.V. All rights reserved.