17 September 1998 Efficiency of aluminized mylar insulation at cryogenic temperatures
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An estimate of the transparency of aluminized mylar `superinsulation' was obtained by measuring the far- infrared/submillimeter wave transmittances of 3 pieces randomly selected from a 25.4 micrometers -thick (nom. 001 in.) sheet of mylar that was aluminized on one side. Measured transmittance values were less than 1 X 10-4 in the 100 micrometers - 1000 micrometers wavelength region. The emissivities of mylar and aluminum were computed from published optical constants to be, respectively, about 5 X 10-2 and 2 X 10-4 for temperatures near 20 K and an effective wavelength of 150 micrometers . Due to the strong attenuation of the aluminum layer, the radiant power from an elemental area on the outer surface of the superinsulation is about 104 times more significant than radiance originating within the insulating mylar layer, for temperatures near 20 K. Radiant power passing through doubly aluminized mylar (the usual configuration) would be attenuated by a factor of about 10-10.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
James B. Heaney, James B. Heaney, "Efficiency of aluminized mylar insulation at cryogenic temperatures", Proc. SPIE 3435, Cryogenic Optical Systems and Instruments VIII, (17 September 1998); doi: 10.1117/12.323733; https://doi.org/10.1117/12.323733


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