MADMAX Cryogenic Stability: Preliminary Design of the Macumba Demo-Coil for Physics

The objective of the MADMAX project, led by the Max Planck Institute, is to detect axion dark matter with a mass of ∼100 µeV. To amplify the detection signal of the photons, induced by the axion conversion, the MADMAX dipole must produce ∼9 T within a 1.35 m aperture where a booster, the signal amplifier, is located. At the current stage of the project a demonstrator, Macumba, is needed for various reasons, i) to show that nominal current operation can be reached with MADMAX, ii) to practice coil fabrication, iii) to train the team that will be in charge of the MADMAX operation at DESY and iv) to start learning about the axion physics. Here is presented the design of the Macumba demonstrator magnet that targets operating conditions close to the final magnet in terms of loadline, mechanical constraints and heat generation. The structure and conductor of the demonstrator must be similar to a MADMAX coil to face the same fabrication issue as for MADMAX coils. This would allow improving the manufacturing procedures and tooling. In addition, Macumba magnet produces a physic-compatible magnetic field in an aperture able to host an R&D booster in preparation for the operation at DESY.