Scanning electron microscopy characterisation of carbon deposited layers in Tore Supra
For long discharges in Tore Supra, an infrared safety system has been installed to survey surface temperature of the target plates located below the Toroidal Pump Limiter (TPL). During the 2002 experimental campaign, the surface temperature of the leading edge of the TPL neutraliser was seen to increase for the same plasma conditions. This is attributed to the growth of a carbon layer at the surface of the neutraliser (approximately 10 square centimetres) located at 4�8 cm outside the Last Closed Flux Surface (LCFS), leading to a temperature increase of about 400°C between virgin and layered surfaces. A difference of surface temperature of about 200 °C was also measured between the top and the bottom of the neutraliser leading edge. According to temperature measurements on the top and on the bottom of the neutraliser, the layer thickness is thicker on the top of the neutraliser, approximately 4 cm apart from the LCMFS, than on the bottom. This has been confirmed by visual inspection. For temperature safety analysis, target plates have been cleaned and carbon layers were sampled for Scanning Electronic Microscopy (SEM) study. SEM analyses, initially aimed at measuring the thickness and finding a correlation between the surface morphology and infrared emission were completed with Energy Dispersive X-Ray Spectroscopy and Time-of- Flight Secondary Ions Mass Spectrometry (ToF-SIMS). Thus, the relative concentration of selected impurities and their profiles through the carbon-deposited layers and indication about the growth mechanism were obtained.
Bibliographic Reference: An oral paper given at: 30th EPS Conference on Controlled Fusion and Plasma Physics Organised by: European Physical Society Held at: St. Petersburg, Russia, 7-11 July 2003 Proceedings available online at: http://eps2003.ioffe.ru/
Availability: Available from Association EURATOM-CEA, Département de Recherches sur la Fusion Contrôlée, CEA Cadarache, F-13108 St Paul-Lez-Durance, France Tel: (+33) 4 42 25 70 01; Fax: (+33) 4 42 25 64 21 E-mail: firstname.lastname@example.org
Record Number: 200317060 / Last updated on: 2003-10-29
Original language: en
Available languages: en