Published By National Aeronautics and Space Administration
Issued mehr als 9 Jahre ago
Summary
Description
<p>We have developed carbon nanotube formulations primarily geared towards enhanced stray light control on a variety of instruments.&nbsp; IRAD has supported development of this technology to make it 10 to 100 times blacker than alternate surface treatments from the Near UV to Far Infrared and a large variety of substrates suitable for space flight instrumentation.&nbsp;&nbsp; In addition, we have performed the first growth on catalyst applied to substrates using Atomic Layer Deposition (ALD).&nbsp; Catalyst is normally deposited using thermal or e-beam evaporation which allows for coating flat surfaces.&nbsp; Many baffles are dimensional, curved or complex, requiring conformal deposition.&nbsp; The development of a conformal nanotube process is enabling to many applications.&nbsp; We have demonstrated ALD of iron catalyst out of house and hope to achieve an in-house capability.&nbsp; Ellipsometry performed on the part verified sub nanometer uniformity of catalyst across a test part .&nbsp; The compact coronagraph baffle is larger and more complex which will pose a significant challenge in maintaining uniformity over a larger third dimension.&nbsp;&nbsp; In addition, we must solve the problem of managing feedstock gas flow in our nanotube furnace during chemical vapor deposition (CVD).&nbsp; We have seen significant shadowing and non uniformity of growth due to laminar flow at substrate edges.&nbsp; Modeling of the gas flow has begun and will be useful in solving this problem.&nbsp; In addition we are performing our occulter growth using a reflector to direct feedstock gas to the shadowed side of the mask.&nbsp; Our goal will be to address these challenges and deliver a solar chronographic mask that is applicable to other scientific observations.</p>
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