A Niobium Superconducting Magnetic Shield for a Low-Field Measurement Laboratory: Sizing, Residual Field and Mass Budget

This paper presents a computed design for a niobium shield intended for low-field magnetic measurement, with its performance, resource budgets and margins derived from stated assumptions rather than asserted. The headline results are: residual interior field change for a 50 microtesla external change of 0.25 nT; budgeted trapped-flux offset after a low-field cooldown of 10 nT; combined residual field budget of 10 nT; effective shielding factor against slow external changes of 2e+05 dimensionless; mass of the niobium shell and end caps of 18.2 kg. Each figure was produced by the deposited computation from the inputs listed in the Methods, and the sensitivity of the conclusions to those inputs is examined in the Discussion. The design is a paper study: it is labelled, on its face and in this abstract, SIMULATED, NOT MEASURED, and no quantity reported here is a measurement of built hardware.