Impurity fluxes and concentrations in the ISX-B beryllium limiter experiment

An experiment to test beryllium as a limiter material has been performed in the ISX-B tokamak. One facet of the studies centred on characterizing impurity influxes and concentrations. The radiation from both low-Z (Be, C, N, O) and intermediate-Z (Ti, Cr) contaminants was measured at the limiter surface and at a wall location 90 deg. away from the limiter to assess the relative contributions of metallic impurities from the two different sources. The effect of limiter melting, with concomitant reduction of both low-Z and intermediate-Z elements, was also documented. The analysis, including atomic rate coefficients, for interpreting spectral radiation in terms of production rates is discussed in detail. (author)