Dewar Assembly
Instrument
The focal plane assembly operates at 58 K for high sensitivity and is packaged in a permanent vacuum dewar which mates directly to the 155 K grating spectrometer. This complex thermal mechanical arrangement in combination with the large number of leads placed great demands on the dewar design. The dewar outer shell is constructed primarily of stainless steel and uses a glass inner bore to accommodate the 58 K/155 K thermal transition. Low loss heat transfer from the focal plane to the pulse tube cryocooler is provided through a single crystal sapphire rod connected to the dewar end well. Attachment of the rod to the cryocooler uses a flexible coupling.
