Proof-of-Principle of an Energy-Efficient, Iron-Dominated Electromagnet for Physics Experiments

A number of physics experiments call for the use of iron-dominated, normal-conducting electromagnets to produce moderate fields (2 T range) in a large gap or over a large volume. Although robust and reliable, these magnets require significant electrical power, in the MW range, and can thus be costly to operate, especially in DC mode. We report on the design and test of a superconducting, proof-of-principle demonstrator that makes use of technological developments carried out for the High Luminosity upgrade of the Large Hadron Collider at CERN (HL-LHC). The demonstrator includes a superconducting coil, wound from a MgB
₂
cable, and mounted inside an iron yoke with a 62 mm gap. As a first phase, the demonstrator was successfully tested in liquid helium at 4.5 K, generating a magnetic flux density of 1.95 T at a current of 5 kA. In a second phase, currently under preparation, the demonstrator will be tested in gaseous helium at 20 K. The design concepts of the demonstrator can be scaled up to large, iron-dominated electromagnets.