Layer by Layer MLI Calculation Using a Separated Mode Equation

Abstract

Introduction of multilayer insulation (MLI) in the late 1950’s had an immediate impact on the cryogenic community. There was a flurry of activity on the part of manufacturers and laboratories to learn how to utilize and evaluate this dramatic improvement in insulation technology. However, by the late 1960’s, MLI had become a generic term for multiple reflector material with and without separators and most laboratories had moved on to other work. Although knowledge of MLI was certainly not complete, it was sufficient for construction of low heat leak dewars and cryogenic apparatus. As the experience base grew, empirical MLI design equations began to appear with some, in particular the “Lockheed”¹ equation, capable of accurately predicting performance of certain combinations of reflector and separator materials. Fortunately, there were individuals who realized that MLI technology was not complete and were able to obtain funding to support continued development. In this category, recognition should be given to Dr. Ron Fast² and his associates at Fermilab, Mr. T. C. Nast³ and associates at Lockheed, and, more recently, Mr. W. N. Boroski⁴ who has been working at Fermilab on behalf of the SSC.