MADMAX
A dielectric haloscope searching for axion dark matter in unexplored energy ranges.
Axions, initially postulated to solve the strong CP-problem, can potentially explain the nature of dark matter in the universe, one of the big open cosmological questions of today.
The international collaboration on the MADMAX project, under the lead of the Max Planck Institute for Physics, is aiming to develop a dielectric haloscope that can search for axion dark matter in the so far unexplored energy regime of 40 to 400 µeV (10 to 100 GHz).
The Electronics division of the MPIfR contributes to this project by sharing our experience and knowledge in the domain of high frequency systems. For this reason, we have been part of the steering comity of these activities. We developed the optics system for the first large scale haloscope prototype, which is currently in final setup at the University of Hamburg and will be used in the CERN Morpurgo magnet for test-measurements. In addition, we provided a data acquisition system to the project at the beginning of 2024 that was based upon our knowledge of backend GPU software. This system was in use as the main data acquisition system during the March 2024 test run at CERN. In this test run, the MadMax consortium was able to extract a limit on dark matter ALP photon coupling exceeding the so far best limit from CAST at the observed frequencies and, in doing so, proved the feasibility of the concept.
MPIfR contributions
The optics for the MADMAX prototype, including its horn antenna, was developed at the MPIfR over the last years. The optics is intended for the laboratory test measurements that will be conducted within the prototype cryostat at the University of Hamburg. For 2026, a first physics run at CERN’s Morpurgo magnet is intended.
During 2023, MPIfR provided a data acquisition system to the project, which is based upon a commercial spectrum analyser, and a GPU-based data processing system running on software developed at the MPIfR. The system is capable of analysing a 512 MHz-wide RF-band in real-time.
Further Information
For a detailed project description, we refer to the project website which describes the experiment including all theoretical aspects in detail. The site also includes a list of all partners involved, shows all milestones reached, and names all publications available so far.
