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Cryogenic Solutions

Cryogenic Test Equipment and Services - Range of services

With over 15 years experience in cryogenic applications, Callisto is able to offer high precision and cost effective cryogenic test equipment and services, for a wide range of applications and sectors.

Callisto’s Dewar (cryostat) designs serve the testing of RF, microwave, electrical and mechanical components at cryogenic temperatures down to 25 or 15 Kelvin (according to the Dewar model). Our Dewar solutions use a vacuum environment and closed loop (cryogen-free) mechanical Helium coolers.

Examples of components requiring testing are listed below, spanning the radio-astronomy, earth observation satellite, air-borne imaging systems, medical imaging and computing sectors:

Callisto has two standard Dewar (cryostat) test platform models (TD-s and TD-c), designed for the testing of RF microwave, electrical and mechanical components. The TD-s is a square format, suitable for long duration testing of components down to 15K, and the TD-c is a circular format, suitable for rapid, automated thermal cycling and batch component testing down to 25K. The two standard models are presented in detail below.

Callisto also manufactures bespoke Dewars for specific client needs, and can offer an in-house testing service (if the test specifications are compatible with Callisto’s in-house platform).

Circular Test Dewar System (TD-c Model) - Description

Callisto is pleased to announce the completion of the design of a new cryogenic test Dewar system for testing of various types of small components including RF, optical, and electronics. This system is cryogen-free (closed-loop helium gas circuit), operates under vacuum and uses a GM-type cryo-cooler. It can cool components as low as 25K.

One of the main features of this system is the capability of automatic thermal cycling between +60°C down to below 40K and back to +60°C within a very short time frame, typically less than 1.5 hrs (depending on test setup).

This system includes 5 large ports located on the sides and on the top of the enclosure that can be used for a variety of hermetic connections to reach the components under test. Two additional small ports are available on the bottom plate, which can also be used for a variety of electrical connections.

The system also features a special cryo-cooler mount, to allow an easy opening and disassembly of the cold chamber containing the components tested (e.g. to transfer the test chamber in a white room to load a batch of components).

The Dewar mechanical design is very flexible. For instance it is possible to either open the lid of the Dewar or the entire Dewar housing to access the components, according to the exact requirements of the test setup.

Purchase options of either a complete Cryo Test System or Cryo Test Service are detailed on the next page.

Parameter Specifications
Base Operation Temperature 25 Kelvin unloaded
Dewar Dimensions H. 700mm x Ø 450mm
Inner dimensions of cold box H. 140mm x L. 160mm x W. 160mm
Test Enclosure Environment Vacuum 10-5 mbar
Cooling Power 140 Watts (@50K)
Mass 45kg
Minimum Test Duration +60°C to 40K to +60°C in typically <1.5hrs
Mean Time Between Services 10,000 hrs
Test Ports 5 ports Ø 80mm, 1 port Ø 30mm
Thermometry 4 diode thermometers
External logging Software for M&C and thermal cycle management running on MSwin XP or 7
Dewar Material Aluminium
Cold Plate Material Aluminium
Accessories Support trolley and rack unit

Test Dewar TD-c Model


The Callisto Test Dewar TD-c Model with Dimensions of H. 700mm x Ø 450mm

Key Features of the TD-c Test Dewar Model

  • Down to 25K tests
  • RF, electronic or mechanical components testing
  • Recording of temperatures and components’ measured parameters
  • Tested component sizes up to H140mm x W160mm x L160mm

Square Test Dewar System (TD-s Model) - Description

Callisto’s TD-s Cryo Test System is based on a square format Dewar, using a GM type cryo-cooler and with up to 7 test connection ports for connections to the inner cold chamber.

These re-configurable access ports can either be for electrical RF connections, with the top window for direct microwave or optical signal inputs.

RF coaxial and/or waveguide test ports may be used depending on the application. Low thermal loss transmission lines are used inside the Dewar to ensure optimum thermal isolation.

The Dewar is equipped with internal thermometers linked to an external computer for logging purposes.

The computer and logger can also record analogue or digital parameters from the test bench, in case that the recording of measured parameters as a function of temperature is required.

The maximum component size which can be accommodated is defined by the cold plate enclosure size of 300mm x 300mm x 100mm.

Purchase options of either a complete Cryo Test System or a Cryo Test Service are detailed on the next

Parameter Specifications
Base Operation Temperature 1st Stage < 50K, 2nd Stage < 15 K unloaded
Test Enclosure Environment Vacuum < 10-5 mbar
Dewar Material Aluminium
Cold Plate Material Aluminium; Nickel plated
Cold Plate Dimensions 300 mm x 300 mm (width/length))
Cool Down and Warm-up Times ~4 hrs cool-down time, ~4 hrs warm-up time (using heating circuit)
Internal clear height above cold plate 100 mm (with optional extension tube (dia. 200mm) to give > 150 mm clearance)
Cooling Power First Stage 8 Watts, Second Stage 6 Watts
Max. Test Duration ~10,000hrs – close cycle refrigerator (mean time between services)
Test Ports Up to 7x ports of 80-200 mm for waveguide, coaxial RF, direct RF feeds or other types of connector.
Thermometry Silicon Diode cryogenic thermometers on first and second stages.
External logging Up to 20 analogue channels and 16 digital lines. Analogue parameters sampled at 60 readings/second (max). PC based data written to ASCII file.
Mass 45kg
Accessories Support trolley

Test Service

Callisto’s test service offer allows clients a flexible solution to evaluate the performance of components at cryo temperatures, priced on a per-test basis and thereby minimising capital expenditure. The comprehensive service includes:

Test Bench Equipment Package

A complete RF Test bench is available to clients for their own in-house component testing. The test solution includes the above described Dewar, cryo-cold head, cryo-compressor and vacuum pump.

Test Dewar TD-s Model

Cryogenic Test Dewar
The re-configurable access ports include a large 200 mm vacuum window on the top plate made of Mylar and PTFE, ideal for IR direct signal reception (e.g. a satellite feed). The window and its extension tube can be removed and replaced by a metal blank plate with sealing ring.

Dewar with top cover removed – cold plate view

Cryogenic Test Dewar

Key Features of the TD-s Test Dewar Model

  • 15K and/or 50K tests
  • RF components (coaxial and/or waveguide), electronic components and small mechanical components testing
  • Recording of temperatures and components’ measured parameters
  • Tested component sizes up to 300mm x 300mm x 100mm.

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