Quantum technologies – such as quantum computers, sensors, and secure communication systems – are expected to transform industry, science, and society over the coming decades. These systems require extremely low temperatures, close to absolute zero, to operate. At present, such cooling is provided almost exclusively by “dilution refrigerators,” which rely on helium-3, a rare isotope produced mainly as a by-product of nuclear weapons programs. Helium-3 is expensive, scarce, and controlled outside Europe, creating a major supply risk for the future quantum industry.
The LEMON project tackles this challenge by advancing continuous Adiabatic Demagnetization Refrigeration (cADR), a proven technology already commercialized by kiutra. Unlike dilution refrigerators, cADR does not rely on helium-3 but uses the magnetocaloric effect, where certain materials cool down when a magnetic field is removed.
What is new in LEMON is the step from today’s small-scale cADR systems to a large-scale version powerful enough to support quantum computers. The project’s objective is to demonstrate a system that delivers 20 microwatts of cooling power at 20 millikelvin – performance that matches the requirements of emerging quantum processors and goes far beyond current cADR capabilities. Achieving this milestone would open the door to even larger machines by replicating the same modular cooling units many times.
The project pathway to impact is clear:
- Scientific impact: establishing cADR as a credible alternative to helium-3 cooling.
- Industrial impact: laying the foundation for future quantum computing and related technologies in Europe.
- Strategic impact: reducing dependency on critical resources from outside the EU, supporting Europe’s technological sovereignty.
Given the projected multi-billion-euro global quantum market, the significance of this work is high. The ability to deliver scalable, helium-3-free cooling may become one of the essential enablers of the second quantum revolution.
