Master Bond EP29LPSP epoxy was cited in a patent granted to S2 Corporation for a cryogenic refrigerator.1 The patented device is designed to cool a sample t < 4K while isolating the sample from vibrations produced by the cooling mechanism. In a closed system cryo-cooler, a single charge of helium gas is pressure-cycled to cool the sample in a continuous refrigeration cycle. A drawback to closed system cryo-coolers is that the constant pressure-cycling transfers vibrations to the sample to be cooled, which could pose a problem for sensitive samples. The patented device provides for vibration isolation of the sample by housing it in a nested thermal insulating structure (NTIS) that is separated from the cryo-cooler via a vacuum shroud. Thermal links exchange heat between the NTIS and the cryo-cooler.
The NTIS consists of three nested thermally insulated tubes made of glass fiber and epoxy resin. The three tubes are attached to each other via two aluminum tube couplers using Master Bond EP29LPSP epoxy. Because the coefficient of thermal expansion (CTE) between the substrates (glass fiber/epoxy and aluminum) is mismatched and there is a wide temperature variation between assembly (300K) and operating(< 4K) conditions, these epoxy bonds must be able withstand several thermal cycles in addition to cryogenic operating temperatures. Due to its ability to withstand thermal shock and its low outgassing and cryogenic serviceability properties, Master Bond LP29LPSP is well-suited for this demanding application.