A scalable implementation of a 3D magnetic Hall sensor card for mapping and monitoring applications

High-energy physics experiments make use of large magnets to bend particle trajectories and thus allow their identification. These magnets, very often custom-built, necessitate an accurate mapping of the generated magnetic field and, in some cases, online monitoring. In both cases, a large number of 3D magnetic field sensors is required, in the order of tens and sometimes hundreds. This article presents the development of an implementation of a 3D Hall sensor card, featuring a custom printed circuit board with a 24-bit ΔΣ analog-to-digital converter, a microcontroller supporting CANopen communication, readout electronics, and an innovative and cost-effective 3-dimensional assembly of the Hall sensor elements, compatible with medium-scale production of up to 200 cards. Initial measurements demonstrate the benefits of the new assembly method and confirm the reliability of the electronic readout in strong magnetic fields up to 1 T. The calibration of the Hall sensor card shows a magnetic field strength measurement precision of 8.8 × 10 -5 T, and angular measurement precisions of 0.083° (polar angle) and 0.666° (azimuthal angle). These results were validated at field strengths of 0.225 T, 0.45 T, and 0.675 T. The findings highlight the potential for ongoing optimization and validation in stronger fields up to 4 T.