Tolerances and uncertainties versus magnetic performance in MECO magnet system

MECO, the muon-to-electron conversion experiment, requires a total of 96 superconducting solenoids designed for construction by industry and assembly into 4 separate cryostats following completion of final design. The magnet system has a 12 × 26 m installation footprint. The objective of the tolerances and uncertainties sensitivity studies was to demonstrate the feasibility of building a MECO magnet system around the conceptual design that meets the performance requirements in the presence of expected material property variances, realistic manufacturing tolerances, and manufacturing and design uncertainties. The study also presents a method for minimizing manufacturing costs by setting adequate tolerances and using the most appropriate manufacturing and assembly procedures. Monte-Carlo magnetic modeling was used to introduce field errors from various possible deviations of the structure from the nominal design, and correlate them with the field performance. The conclusion from the study is that the design is robust. Field requirements are met in the presence of material property uncertainties and modest machining and assembly tolerances. This implies that the project may be able to accept field quality risk and ask the fabricator to accept only the responsibility for placing the coils with correct turn counts in their warm positions at reasonable tolerances.