World leaders in sub-Kelvin cryogenics

Our customers’ applications include astrophysics, quantum technologies, nanotechnology, materials science and life sciences.

With an emphasis on compact, low power and easy-to-use technologies, we are constantly working to innovate and extend our product range, offering relatively low cost options for reaching sub-Kelvin temperatures. Our new products extend the base temperatures, heat lifts and run times achievable with compact, sorption technology. Contact us to discuss whether we can meet your requirements.

Cool to below 1 Kelvin


Low-cost, easy to operate, reliable and effective. Our 1K sorption cooler modules interface to either a mechanical (GM/PT) cryocooler or the 4K plate of a ‘wet’ dewar. We can offer a number of interfacing options to accommodate a cold table housing the end-user application. Just contact us to discuss your requirements.
Popular applications for these sorption coolers include quantum computing, superconducting nanowire single-photon detectors (SNSPDs), superconducting electronics and semiconductor wafer testing. You won’t find a simpler way to reach temperatures below 1K.

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The CC4 is a compact 1K continuous cooler that has been designed to be interfaced to a low-power GM cryocooler. The initial cool down time can be slow (approx. 24 hours) but this can be reduced by adding an optional heat switch, or by using a more powerful 4K cryocooler.

The CC4 has two helium 4 modules. Each 4-module works like a single-shot GL4 sorption cooler; the modules are cycled alternately to keep the central 1K-head permanently cold, i.e. the run time of the CC4 is unlimited when the CC4 is run under software control. The 1K-head temperature typically shows small fluctuations at the ‘handover’ between the two modules. However there are many possible optimisation schemes that the end user can employ to obtain the best possible performance for their own application. As a general rule, there is a trade-off between low temperature and temperature stability, i.e. lower fluctuations come at the cost of slightly higher average temperature.

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Cool to below 300 mKelvin


Gram per gram, Helium 3 is the world’s most expensive substance. CRC’s gas-light sub-Kelvin sorption coolers have been designed to make the best possible use of this scarce resource. By buffering the ultra-cold stage with either one or two intermediate stages, we reduce the heat load on the ultra-cold head and hence lower the running temperature and lengthen the run time. As our coolers are sealed systems, no helium gas is consumed during operation and our units never need to be recharged or re-filled. Our latest design, the 300mK continuous cooler, even offers unlimited run time.

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Our GL10 single-shot sorption cooler adds an extra ultracold stage to the GL7. The load buffering provided by this additional stage enables the unit to reach a base temperature below 250mK, with sizeable heat buffering capacity at several temperatures points below 4K. It is even possible to add a second ultracold stage to the GL10 to increase the cooling power at the lowest temperature, see an example of the GL10 Twin in the Gallery.


The CC7 is a compact continuous ~300mK sorption cooler that is designed to interface to a low-power GM cryocooler. The CC7 has two helium 3 and two helium 4 modules. Each 3-4 module set works like a conventional two-stage (GL7) single-shot sorption cooler. The two ‘sides’ of the CC7 are cycled alternately to keep the central split condenser permanently cold. The split condenser is the cold head of the CC7.

The CC7 is run under software control to operate the switching sequences required to keep the unit running indefinitely. The CC7 split condenser shows small temperature fluctuations when the cycle hands over from one side to the other. There is considerable scope for the end-user to smooth out these fluctuations; the best optimisation scheme will depend on the cryogenic environment and on the heat load this imposes on the CC7. Residual fluctuations can be smoothed out using PID feedback to a load resistor mounted on the split condenser, though this will increase the average temperature of the split condenser.

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Cool to below 100 mKelvin


Cool to the max by using the latent heat of enthalpy produced as liquid Helium 3 dissolves in liquid Helium 4. Once again, our Continuous Miniature Dilution (CMD) coolers are compact, sealed units that need no external gas supply and will never need to be refilled with expensive Helium 3. The CMD incorporates our 300mK continuous cooler (CC7) to pre-cool and buffer the dilution module. If you are interested in the potential applications for this unique cooling technology, get in touch with us to discuss your needs and how we might help.

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Heat Switches

Active Heat Switches

In an active heat switch a small external gas absorber pod is connected by a gas tube to the foot of the switch. Gas is released into the switch by electrically heating the pod under user control. The thermal conductance in ON and OFF states depend on material properties of the gas and the heat switch shell, and on the temperatures at the ‘hot’ and ‘cold’ ends.

An ideal heat switch would have high on-state conductance and very low off-state conductance. In practice it is very challenging to manufacture a gas-gap heat switch that meets both criteria. The space available to accommodate the heat switch is an additional constraint.

To find out whether we can provide a heat switch for your particular requirements, use our Heat Switch Questionnaire to let us know more about your intended application.

Passive Heat Switches

A passive switch has an internal absorber and operates automatically; it turns ON and remains fully ON while the hot end temperature is greater than around 15-20K. In the ON state the thermal conductivity is large (around 100mW/K at 4K). When the hot end temperature drops below around 10K the switch will start to turn OFF though it will not be fully OFF until the hot end temperature is ~4K. When the switch is OFF it has a residual thermal conductance dictated by the material properties and dimensions of the shell.

To find out whether we can provide a heat switch for your particular requirements, use our Heat Switch Questionnaire to let us know more about your intended application.

Custom Design and Build

All of our products can be adapted to suit your requirements.

We can customize our GL4, GL7 and GL10 products to optimise them for the user’s applications, for example to offer either a shorter or a longer run time, or higher load capacity, or to interface to a customer’s existing cryostat. Some examples of the many custom coolers that we have made for specific applications are pictured in our Gallery. Contact us to discuss whether we can design and build to meet your particular application.

Custom GL4
Folded GL7
Active switches

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