کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5444078 1511027 2017 21 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Transmissivity testing of multilayer insulation at cryogenic temperatures
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد مواد الکترونیکی، نوری و مغناطیسی
پیش نمایش صفحه اول مقاله
Transmissivity testing of multilayer insulation at cryogenic temperatures
چکیده انگلیسی
The problem of degraded emissivity of thin films at low temperatures has been a long observed phenomena. Previous efforts at measuring properties have suggested that transmission of energy through the films may play a key role in the thermal performance of multilayer insulation systems at low temperatures. Similarly, recent testing on tank applied systems has suggested a radiative degradation at low temperatures. Two different approaches were used to attempt to measure the transmission of energy through MLI at low temperatures. A laser based measurement system was set up to directly measure transmittance and a calorimetric based measurement system was used to measure relative emittance of a single layer between aluminum foil and double aluminized Mylar. Minimal transmission at long wavelengths were observed through standard MLI blanket materials at deposition thicknesses of even 35 nm. Where transmission was measured, it was too low to effect the performance of a multilayers system. Similarly, the calorimeter showed similar increases of emissivity for both standard blanket materials and aluminum foils. Multiple different methodologies of measurement have all yielded the same result: that there is no transmission through standard MLI blanket materials at wavelengths associated with temperatures as low as 2 K.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cryogenics - Volume 86, September 2017, Pages 70-79
نویسندگان
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