Prototyping a Dielectric Axion Haloscope

• Applicant: Professorin Dr. Erika Garutti
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545526387

The axion is a viable and natural candidate for cold dark matter. The theoretically favored mass range for the discovery of axions around 100 μeV, can be investigated using a dielectric haloscope. The MAgnetized Disk and Mirror Axion eXperiment (MADMAX) will be one of the first axion haloscope based on this approach, utilizing the axion photon conversion at dielectric surfaces in a strong magnetic field. By combining many surfaces, the conversion can be boosted significantly using constructive interference and resonances. MADMAX will feature a booster system consisting of up to 80 dielectric disks with more than a meter diameter which can be precisely positioned at cryogenic temperature and inside a 9 T magnetic field created by a superconducting dipole magnet with a large warm bore. Towards the realization of this demanding apparatus, the MADMAX collaboration has developed a staged approach of various prototypes to prove different aspects of the haloscope booster concept. In this project, we aim at commissioning and exploiting at 4K and under 1.6 T magnetic field HALOX, a prototype of a dielectric haloscope with three disks of 300 mm diameter, to ultimately perform an improved axion search. The reduced size prototype is a mandatory step to prove the technical feasibility of the project. Additionally, we plan on upgrading HALOX after the first axion search from three to six discs, and with tiled lanthanum aluminate disks to further improve its sensitivity. The competences of the groups at Centre de Physique des Particules de Marseille (CPPM) in France and the University of Hamburg (UHH) and DESY in Germany are complementarity and synergetic for the realization of HALOX. Via the project the collaboration between the institutes will be strengthened and supported with concrete measures: person-power dedicated to teamwork across the institutes, travel funds supporting long period exchanges, support for the development of innovative technologies in the Franco/German consortium, and support for the physics run of HALOX at CERN. The funding request of the project is developed over 3 years, dedicated to the commissioning and tests of the prototype (2025), its exploitation towards first physics results (2026) and its upgrade (2027). This ambitious and innovative project, with close connections between scientists and engineers of Universität Hamburg, DESY and CPPM, as well as possibilities for connections and exchanges of PhD students, offers a unique scientific potential coupled with several promising technological opportunities.

• DFG Programme: Research Grants
• International Connection: France
• Partner Organisation: Agence Nationale de la Recherche / The French National Research Agency
• Cooperation Partner: Fabrice Hubaut, Ph.D.