Magnetic Measurements for a MICE Spectrometer Solenoid

The goal of the Muon Ionization Cooling Experiment (MICE) is to demonstrate muon cooling for a future muon collider. In order to quantify this cooling effect with high precision, scintillating fiber trackers in a uniform 4 Tesla field are required. The MICE spectrometer solenoids were designed to meet these requirements. Based on superconducting niobium-titanium (Nb-Ti), each of the two MICE spectrometer solenoids consists of five separate coils contained in a vacuum vessel of 2.7 m length and 1.4 m diameter. In this paper, we report on results from first measurements to verify initial magnet performance at the manufacturer site using a portable Hall-probe-based measurement system. A comparison with theoretical expectations based on OPERA simulations will be discussed and design aspects of the measurement system will be presented.