Technical specifications
Ports (optics/electrical feedthroughs) Four on the side of the cryostat *
Maximum port clear aperture 28 mm (77 K radiation shield limit)
Electrical connector (standard) 10 pint low-voltage electrical connector
Optic axis height 20 mm
Headroom (when cold) 77 mm
(Helium temperature) cold plate diameter 200 mm
Liquid helium capacity 4.5 litres
Liquid nitrogen capacity 4.3 litres
Hold time, subsequent fill (typical, not including initial fill) > 20 days (ports blanked, no wiring)
  8-10 days (reduced band mm detector)
  5 days (broadband mm detector) 
Liquid nitrogen hold time (approx) 36-50 hours
Cryostat diameter 299 mm
Cryostat height (excluding lifting handle) 555 mm
Mass (empty) 32.5 kg
* Downward looking optics also available. 
Over-pressure relief valves are located on both the cryostat top plate and central neck baffle.  

This dual reservoir cryostat has a 77 K liquid nitrogen Dewar and jacket, with an intermediate 40 K helium gas cooled radiation shield. This surrounds a 4.2 K liquid helium central Dewar. The cryostat is intended for use throughout the working week and has a liquid helium hold time of five to ten days depending on application. The liquid nitrogen hold time is typically thirty six to fifty hours. 


Readying the cryostat for operation i.e. evacuating and cooling to 4.2K (liquid helium temperature), can be carried out in about fourteen hours. This includes a twelve hour liquid nitrogen pre-cool. The longer pre-cool of this cryostat, when compared to the TK1810 and TK1813 cryostats, is recommended so that the gas cooled radiation shield has time to reach 77K before the liquid helium is transferred into the cryostat. If you are in a hurry a shorter pre-cool can be carried out, but this will require excessive use of the more expensive liquid helium cryogen. Refer to the manual for further details.

TK1840 coldplate

We often customise cryostats to suit customer applications. For example, extended radiation shields can be made that give a greater height above the 4.2K cold plate to accommodate larger apparatus. A mini-refrigerator, or bespoke customer equipment can then be mounted in the cryostat.