Herschel Cryostat
Date: 19 September 2007
Satellite: Herschel
Depicts: Different parts of the cooling system
Copyright: ESA/AOES Medialab
Helium gas boils off from within the helium II tank, after which it flows through a system of pipes around the focal plane units (FPUs) of the three instruments to cool them down. The FPUs are covered by the optical bench shield, seen here at top.
After passing the FPUs, the gas continues to flow through pipes (highlighted in blue) between three successive thermal shields depicted in transparent brown colour. These are cooled by the helium gas to 30K, 50 K and 60 K, respectively from the innermost shield outwards.
Under the "related images" in the right-hand navigation are two illustrations, with one showing the complete cryostat vacuum vessel and one showing the cooling of the three FPUs on the optical bench (without the optical bench shield).
