A company seeks alternative ways of preparing crucibles for the vapor deposition process. Currently, up to a kilogram of an alkalihalide salt is melted electrically in a tantalum crucible within a vacuum chamber, and the vapor is deposited on a metal substrate. The resistance, conductivity, and heating patterns of each crucible — and the vapor cloud it produces — vary from crucible to crucible. The pattern of the cloud changes over time as crucibles age. A thick layer of an inorganic salt — between 400 and 500 micrometers — must be deposited on a metal substrate with microscopic evenness and regularity.
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