12 July 1996 Processing of mercurous chloride in reduced gravity
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In a joint experiment between the Northrop-Grumman Science and Technology Center and the University of Alabama in Huntsville, Consortium for Materials Development in Space, single crystals of mercurous chloride were grown in the Space Experiment Facility (SEF) transparent furnace that was flown on Spacehab 4 in May 1996. Mercurous chloride is an acousto-optical material with an unusually low acoustic velocity and high acousto-optical figure of merit. Single crystals of this material can be readily grown in normal gravity by closed-tube physical vapor transport, but the crystals generally contain structural inhomogeneities which degrade the optical performance. The nature and cause of these defects are not completely understood, but their degree appears to correlate with the Rayleigh number that characterizes the convective transport during their growth; hence, it is suspected that uncontrolled convection may play a role in the defect structure. The objective of the flight experiment was to reduce the convective flows by several orders of magnitude to see if the structural inhomogeneities can be reduced or eliminated. This paper will describe the physical and thermal properties of the SEF furnace, the ampule design and loading procedure, and the ground testing, and will also present the preliminary flight results.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
C. Watson, C. Watson, N. B. Singh, N. B. Singh, A. Thomas, A. Thomas, A. E. Nelson, A. E. Nelson, T. O. Rolin, T. O. Rolin, J. Griffin, J. Griffin, G. Haulenbeek, G. Haulenbeek, N. Daniel, N. Daniel, J. Seaquist, J. Seaquist, C. Cacioppo, C. Cacioppo, Jerry Weber, Jerry Weber, Maria Ittu Zugrav, Maria Ittu Zugrav, R. J. Naumann, R. J. Naumann, } "Processing of mercurous chloride in reduced gravity", Proc. SPIE 2809, Space Processing of Materials, (12 July 1996); doi: 10.1117/12.244337; https://doi.org/10.1117/12.244337

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