Tungsten (W) targets have been exposed to high density (n(e) <= 4 x 10(19) m(-3)), low temperature (T-e <= 3 eV) CH4-seeded deuterium (D) plasma in Pilot-PSI. The surface temperature of the target was similar to 1220 K at the center and decreased radially to similar to 650 K at the edges. Carbon film growth was found to only occur in regions where there was a clear CII emission line, corresponding to regions in the plasma with T-e >= 2 eV. The maximum film thickness was similar to 2.1 mu m after a plasma exposure time of 120 S. He-3 nuclear reaction (NRA) analysis and thermal desorption spectroscopy (TDS) determine that the presence of a thin carbon film dominates the hydrogenic retention properties of the W substrate. Thermal desorption spectroscopy analysis shows retention increasing roughly linearly with incident plasma fluence. NRA measures a C/D ratio of similar to 0.002 in these films deposited at high surface temperatures. (C) 2009 Elsevier B.V. All rights reserved.