  The thermal stability of 200 nm thick plasma enhanced chemical vapor
deposited a-C:H and a-C:D layers ranging from soft to hard layers has been
studied and compared to that of deposits collected on the Tore Supra tokamak
plasma facing components by means of in-situ Raman spectroscopy. Linear ramp
heating and long term isotherms (from several minutes to 21 days) have been
performed and correlations between spectrometric parameters have been found.
The information obtained on the sp 2 clustering has been investigated by
comparing the G band shift and the 514 nm photon absorption evolution due to
the thermal treatment of the layer. The effects of isotopic substitution have
also been investigated.
