Progress update: Reaching lower base temperatures in LEMON

February 2026

Over the past months, we have made measurable progress toward the goal of scalable, helium-3-free magnetic cooling within the LEMON project. A key indicator of this development is the steadily decreasing base temperature achieved in our cryogenic test system.

The figure shown here summarizes this development over time. It starts with results obtained during the preceding SPROUT activities, which established the initial performance baseline. Building on this foundation, successive measurement campaigns within LEMON demonstrate a clear trend toward lower base temperatures as core components are systematically improved and validated.

These results directly reflect advances in Work Package 1 (Technology Validation). Improvements in critical subsystems – including refrigerant packages, thermal interfaces, and thermal switches – are now translating into measurable system-level performance gains. Achieving lower temperatures confirms that the chosen development path is effective and that key risks are being successfully reduced.

In parallel, Work Package 2 (System Design) is advancing, using the validated component data from WP1 to shape the architecture of the full LEMON demonstrator. Together, these developments mark an important step toward large-scale, continuous magnetic cooling for future quantum technologies.