Advances in Multilayer Insulations

Abstract

It Is generally accepted that there are two outstanding types of modern high-quality cryogenic insulations. The first group consists of opacified powders and the second is the so-called superinsulations which are of multilayer construction. Table I compares the outstanding characteristics of the two types of insulation. The advantages of powders are:

• 1. The vacuum requirement is much less stringent for achieving full performance. Usually a pressure of several μHg is quite acceptable, while super-insulations require a pressure not higher than 0,1 μHg.

• 2. They are relatively easy to apply, even to complicated shapes of the insulation space, while multilayer insulations require special techniques to achieve economical installation.