Towards a Micro milliKelvin Cooler Array

Lead Research Organisation: University College London
Department Name: Mullard Space Science Laboratory


This application seeks to demonstrate a 4 K to millikelvin micro cooler through the demonstration of a new concept. Low temperature cryogenics has always been a relatively large scale technology i.e. dilution refrigerators and adiabatic demagnetisation refrigerators (ADR). Recent advances at MSSL in the millikelvin cryocooler (mKCC), solid state heat switches and magnet design enables a new concept of cooling in the 4 K to millikelvin region which enables a dramatic reduction in size. For example, the mKCC which provides 1 uW of cooling power at 100 mK, could be reduced from 5.6 (d) x 12 (w) x 30 (h) cm to a size of 4 (d) x 5 (w) x 5 (h) cm by using the new micro cooler concept. The ultimate coupling of this millikelvin micro cooler to higher temperature micro coolers, offers the prospect of a complete 300 K to 100 millikelvin micro cooler that could be used to cool state-of-the-art cryogenic detectors (e.g. Microwave Kinetic Inductance Detectors MKIDs) and quantum computers in a very compact, portable system. In this application we seek the funds to demonstrate this concept by constructing a small prototype system which will have a continuous 100 mK cooling power of 0.3 uW, when interfaced at 4 K and have predicted dimensions of only 3 x 2 x 5 cm. This concept enables very easy adaptation for higher cooling powers and lower temperatures.

Planned Impact

Low temperature cryogenics is a critically important enabling technology of commercial significance that can be exploited in a number of different fields e.g. detector systems (medical and security), scientific instrumentation and computing (quantum computing), with the key requirements being compactness and ease of use. It is important that users and instrument developers no longer have to be specialists in ultra low temperature (ULT) technologies in order to use it. For applications using low temperatures (e.g. cryogenic detectors) outside the specialist research domain e.g. security and medical imaging, the cooling technology needs to be small and invisible to the user. Technology miniaturization, especially on a scale enabled by the proposed project, will provide significant increase to commercial opportunities and scientific capabilities. The potential of a complete micro cooler from 300 K to millikelvin offers the prospect of portable systems, which is a vision unheard of before the prospect of micro coolers and this application. In a recent article by J Ullom, of the National Institute of Standards and Technology (NIST) "Will ultralow temperatures leave the research lab", Cryogenic society of America, (1/4/2013) (, he states, "Subkelvin sensors are under development for a wide range of applications, including precision x-ray, gamma-ray and alpha-particle spectroscopy for materials analysis, optical photon-counting for advanced telecommunications and submillimeter or THz sensors for concealed weapons detection". "Peering into the future, .... the use of ULTs will become even more widespread. Further dissemination will require a combination of motivating applications and the existence or development of refrigeration technology suitable for these applications." "ADRs are generally attractive; their operating principle is very simple, they use no fluids and they require very little supporting hardware". The miniaturized continuous cooling technology proposed in this application will have an impact. The reduction in size of the 4 K to 0.1 K cooling element to a few centimeters in size is a first step in the realization (combined with higher temperature micro coolers in the future) of an unparalleled opportunity to reduce the size and complexity of a technology in which so far has been complex in operation and large. Miniaturisation will enable low temperature devices from the research lab to be much more easily moved into the applications and commercial world. In summing up Ullom states in his article "However, whether the dissemination of ULTs will truly be widespread depends on whether large cost reductions are possible in the future or whether large simplifications in the cooling process can be achieved". The micro cooler presented here will achieve a high proportion of the path to simplification of cooling. The UK has a very strong commercial low temperature industry comprising both large (i.e. Oxford Instruments) and several SMEs (e.g. ICEOxford, Cryogenics, Scientific Magnetics etc). The proposed cooler development will provide a technological enhancement to them and enable the UK to capitalise on emerging markets for low temperature devices in the areas described in the proposal due to our proposed simple micro cooler.


10 25 50
Description Demonstration of technology required to miniturize very low temperature cooling that will be required for the utilisation of single photon detectors in more wide spread applications.

technology demonstration applicable to room temperature magnetic heating and cooling in order to address climate change.
Exploitation Route The findings are all ready being put to use with a defence project using the results of this work a key part of the project. The work in this project was critical in the award of an EPSRC fellowship.

The out come of this project is being used to investigate green alternatives to heating and cooling to help acheive net zero carbon emissions from heating and cooling
Sectors Aerospace, Defence and Marine,Energy,Environment,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology,Security and Diplomacy

Description Two key impacts in order to realise the cooler array are 1: The understanding of heat transfer by electrons in a sub millimetre sized metalic structure. This is required in order to obtain a compact mm to cm sized sub kelvin cooler. The second impact is the design of superconducting magnets that can ramp to 2 tesla magnetic field in 1 to 2 seconds. Both these impacts have been meet which will enable micro sized cooleres for advanced single photon cameras.
Sector Aerospace, Defence and Marine,Energy,Environment
Impact Types Societal,Economic

Description future low low temperature physics
Geographic Reach National 
Policy Influence Type Participation in a advisory committee
Impact Advisory to the future development of commercial low temperature cryogenics manufacture in the UK
Description sussex quantum technology steering comittee
Geographic Reach National 
Policy Influence Type Membership of a guideline committee
Description Standard grant
Amount £673,107 (GBP)
Funding ID EP/P022898/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 08/2018 
End 10/2019
Description Correlated electronic states for cryogenic refrigeration 
Organisation University of Cambridge
Department Department of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution Low temperature materials testing of new metallic refrigerants for millikelvin cooling
Collaborator Contribution development of new metallic refrigerants for millikelvin cooling
Impact Non yet early days in the project
Start Year 2016
Description Quantum microwave sensor 
Organisation University of Sussex
Country United Kingdom 
Sector Academic/University 
PI Contribution millikevlin cryo cooler
Collaborator Contribution microwave single photon sensor
Impact to early as yet
Start Year 2015
Description school visits 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation Workshop Facilitator
Geographic Reach Regional
Primary Audience Schools
Results and Impact provide science workshops for regional primary schools every year. Approximately 1100 primary school children attend every year

response from schools was that we provide inspiration to the children. Children have gone on to study science at secondary school with more enphusiasm
Year(s) Of Engagement Activity 2006,2007,2008,2009,2010,2011,2012,2013