This progress report covers continuing work to develop a temperature probe for a coal gasifier. A workable probe design requires finding answers to crucial questions involving the probe materials. We report on attempts to answer those questions. We attempted to measure the laser-input power at a wavelength of 355 nm that would damage the ends of sapphire fiber optics. We were surprised and pleased to learn that they survived an input power density of about 3 x 10{sup 9} W/cm{sup 2}, which greatly exceeds the best that fused-silica fibers can do. During a run of our new simulator to obtain an upgraded calibration curve for the improved YAG:Dy phosphors, we found that the phosphor appeared to form a eutectic, with the fused-silica cuvette used to hold the phosphor, when the temperature exceeded 1450 C. This result could have substantial ramifications in this and other high-temperature applications. Our new proprietary detector package that replaced the original photomultiplier tube gave excellent results, with much better signal-to-noise ratio at a given temperature than the old package. Our new plasma-spraying operation has succeeded in spraying YAG, which we think may be a technological breakthrough.

This progress report covers continuing work to develop a temperature probe for a coal gasifier. A workable probe design requires finding answers to crucial questions involving the probe materials. We report on attempts to answer those questions. We previously reported an apparent anomaly in the high-temperature behavior of fused-silica optical components. This time, we report on further anomalies in other components. These unexpected results impede or prevent acquiring data related to the project. The commercial manufacturer of gasifier probes had agreed to lend us three ceramic inner sheaths and one outer sheath for experimentation. He subsequently sent us one inner sheath. We designed a test fixture to be used in a proposed test of phosphor material in a reducing environment at a power company's test facility. Funding delays outside our control caused a related project to be put on hold. Because the two projects shared travel funds, we are unable to continue experimental work until funding resumes. Meanwhile, we are doing some of the labor-intensive data reduction for our recent calibration curves.