Temperature Controlled Stage Systems
A variable temperature controlled stage can be installed in a LHe or LN2 dewar with a 5 inch or larger cold plate. LHe systems are controllable from 5K to 150K and LN2 systems are controllable from 80K to 325K.

Enhanced Helium Hold Time
We offer an intermediate vapor cooling shield that increases the liquid helium hold time on our HDL Series Dewars. The intermediate shield is located between the LN2 vessel and LHe vessel. These systems are capable of vapor cooled shield temperatures of 31 K. Using the intermediate vapor cooling the helium vessel hold time will be increased by 30% as compared to our standard HDL models.

Extended Work Area
Case extensions are useful for a wide variety of applications requiring a large cold work area such as cooled spectrometers and monochrometers.

Up-looking LHe Cryostats
We offer a unique up-looking LHe cryostat used in high altitude, balloon-borne applications. We also make systems used to house demagnetization refrigerators.

Case and Radiation Shield Extensions (increase “B” dimension)
The “B” dimension refers to the vertical distance from the cold work surface to the radiation shield.  When larger than standard amounts of work space are needed, both the case and radiation shield lengths may be increased.

Custom Hole Pattern on Cold Work Surface
The standard pattern of tapped holes in the copper bottom plate may be modified to accommodate special requirements.

Exterior Finish
The exterior finish of all dewars and refrigerators is anodized aluminum.  Gold is the standard color, however, blue, red, green, and black are also available.

High Altitude / Balloon Modification
When the case of a dewar must be operated at temperatures well below the standard range, indium o-ring seals are substituted for the standard butyl o-rings.

Increased LHe and/or LN2 Capacities
For each vessel diameter, the standard length nearly equals the diameter.  For additional capacities, without increasing the diameter, the length of the vessel is increased up to a factor of two.  For larger increases in capacity and hold time, it is better to increase the diameter.

Inverted Operation
To facilitate direct optical access to the work space from above, a modification may be added that allows the dewar to operate inverted without significant penalty in hold time.  Large windows may be accommodated in this configuration.

LHe Cooled Radiation Shield
To provide additional rejection of incident IR backgrounds within the dewar, a shield may be added which attaches directly to the cold work surface.  Usually, this shield is fitted with a removable bottom plate similar to the standard shield.

Low Temperature Modification for LHe Dewars
To facilitate pumping the LHe bath to temperatures below 1.4 K, the neck tube is modified.  This modification permits temperatures as low as 1.2 K.

Low Temperature Modification for LN₂ Dewars
To pump liquid nitrogen below the triple point, copper webbing is added to the interior of the cryogen vessel.  This webbing increases thermal contact with the solid nitrogen and allows for effective cooling.

Rigid Support System
Standard dewar supports are designed to provide excellent hold times. When greater strength is needed to meet special mechanical requirements, a more rigid support system is used in place of the standard system. 

Split Case and Radiation Shield
To provide direct access to the work space, the case and radiation shield are modified by insertion of demountable joints at the proper location.