Conductor Design of the Madmax 9 T Large Dipole Magnet

The Madmax (MAgnetized Disc and Mirror AXion) project is an experiment dedicated to the discovery of the axion particle, the mass of which is expected to lie in the range of 100 μeV. To detect the axion, a dipole field with a square-field integral value of 100 T2m2is required. This field spread over 2 meters along the axis to put a booster to amplify the photons before the detection. The conductor has been designed to minimize the global magnet cost while fulfilling the following constraints: the hot spot temperature must stay below 100 K, the voltage to ground below ±1 kV, and mechanical Von Mises stress below 190 Mpa. This will be the world largest dipole block type, with a warm bore of 1.35 m and a center field of 9 T. Its overall total length is of about 6 m, the total weight is of 200 tons, including 40 tons for the windings. NbTi technology was selected. The engineering current density is fixed at 50 A/mm2and the nominal current is 23.5 kA according to the protection principle. The large forces over the conductor blocks will induce some displacements. To guarantee the magnet stability a superfluid helium channel is located in the conductor stabilizer.