The Solenoid Magnet and Flux Return for the PANDA Experiment

The design of the solenoidal magnet developed by INFN Sezione di Genova, for the PANDA detector at FAIR (GSI, Darmstadt) is presented here. This is a thin, superconducting coil made using Rutherford-type, aluminum stabilized cable, indirectly cooled using circulation of two-phase helium in a network of pipes welded on an external coil former. The concept of this magnet is the same of many detector magnets, such as BaBar, Finuda, Delphi, CMS and many others: we took them as a guideline, keeping all the critical parameters under the values obtained in working magnets. The way the magnetic (2 T central field, plusmn 2% uniformity, small radial field), thermal (1.8 K safety margin, safe quench behavior) and mechanical ( ~ 100 t magnetic force compensation, path load for nested detectors) requirements were fulfilled is shown here.