Continuous Flow Cryostats

Continuous Flow Cryostats (CFCs) are cooling systems, first developed by ESO, based on an automatic refilling (using a continuous circulation of LN2) with the following advantages:

  • They are more compact, lighter and smaller than traditional LN2 bath cryostats
  • They have less associated vibrations than standard cooling systems, ideal for stable environments
  • They do not require daily human intervention, thus improving maintainability
  • They behave safely in case of power failure
  • Control solution based on Beckoff PLCs

CFCs allow the temperature within an instrument to be changed from room temperature ~ 290 K to ~ 80 K.

FRACTAL S.L.N.E. signed an agreement with ESO to access this technology (see ESO News 9 of June 2015) and can produce these elements as per client request.

  • 4 Continuous Flow Cryostats (CFCs) for ESO have been already manufactured, integrated and verified (3 lateral and 1 axial were delivered).
  • A CFC prototype has been integrated and tested with the controller and control system based on Beckhoff technology developed by FRACTAL (see presentation at RIA-TEC2SPACE).

Applications for Astronomy

  • High resolution spectrographs are the most obvious applications being very sensitive to any sort of disturbances (i.e. UVES, HARPS, CARMENES, ESPRESSO)
  • Nasmyth rotating instruments offering a constant weight and not affecting the instrument from any change of gravitational load as traditional bath cryostats (i.e. NACO and VIMOS)
  • Multiple detector systems as those that combines several spectrographs (i.e. MUSE) making maintenance easier