Magnetic cryostat

• Subject Area: Particles, Nuclei and Fields
• Term: Funded in 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 553828235

High-field magnet systems, which allow data-taking at temperatures close to absolute zero, are playing an increasingly important role in answering questions in fundamental physics. The large-scale device applied for is a cooling system with an integrated high-field magnet with a field strength of 12 T in a magnetic volume of 1200 cm3 at a temperature of 10 mK. The device forms the basis for searches for axion-like particles, high frequency gravitational waves as well as other phenomena beyond the Standard Model of particle physics. The magnet system will allow to generate laboratory conditions in which those fundamental physics processes can be studied, that would otherwise escape our detection. In fact, the magnetic field is the place where the relevant physics processes occur. The search for axions will be based on a haloscope approach, i.e. the operation of an electromagnetic cavity in a high magnetic field. Due to the small expected induced signal, the cavities must be operated at extremely low temperatures to suppress thermal noise. The proposed device will make it possible to test models of axion-like particles in a mass range from 15ueV to 40ueV with unprecedented sensitivity. Parallel to this, searches for high-frequency gravitational waves will be carried out using similar electromagnetic cavities at low-operating temperatures in high magnetic fields. A different experimental scheme is used for the search for photon charges analogous to the Aharonov-Bohm effect. Here the available volume of the magnetic field as well as the field strength is crucial. Beside the applications in the context of fundamental physics, the magnet system will also be used to test the stability of electronic systems of future particle detectors, which are operated in strong magnetic fields.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Magnet-Kryostat
• Instrumentation Group: 8550 Spezielle Kryostaten (für tiefste Temperaturen)
• Applicant Institution: Rheinische Friedrich-Wilhelms-Universität Bonn
• Leader: Professor Dr. Matthias Schott