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Advanced techniques are presented which facilitate the development of inert or reducing atmospheres in excess of 2000 K in order to improve processing of containerless capabilities at higher temperatures and to provide more contamination-free environments. Recent testing, in the laboratory and aboard the NASA KC-135 aircraft, of a high-temperature acoustic positioner demonstrated the effectiveness of a specimen motion damping system and of specimen spin control. It is found that stable positioning can be achieved under ambient and heated conditions, including the transient states of heat-up and cool-down. An incorporated high-temperature levitator was found capable of processing specimens of up to 6-mm diameter in a high-purity environment without the contaminating effects of a container at high temperatures and with relative quiescence.

A measurement technique is described that is capable of producing accurate numerical maps of the parallelism defect of optically contacted Fabry-Perot etalons. A photoelectric raster scan of the etalon transmission intensity distribution is performed at each of three closely spaced etalon tunings, one at maximum on-axis and two at the half-maxima on-axis positions. Simple data manipulation gives numerical or contour maps of the parallelism defect. Results demonstrating the effect of mechanical constraints on etalon parallelism are presented