Operational history of stainless steel, TiC, TiB2, and boron limiters in the ISX-B tokamak

For the past eighteen months a variety of low-Z coatings have been tested for service as limiters in both ohmically-heated and beam-heated ISX-B plasmas. To date TiC, TiB 2 , and B coatings on a graphite substrate have been examined with TiC providing the best results of the three. The history of these materials in ISX-B is reviewed and compared with previously used stainless steel limiters with particular emphasis on machine performance.