SQUIDsensorer

SQUIDsensorer is a class of ultra-sensitive magnetic sensors that builds on superconducting quantum interference devices (SQUIDs) to detect extremely weak magnetic fields. It is described in some research contexts as a modular platform combining SQUID sensors with advanced cryogenics and electronics to enable high-sensitivity, multi-channel field mapping in laboratory and field environments.

The core is a superconducting loop containing Josephson junctions, operated in a flux-locked loop to convert magnetic flux into a voltage with high linearity. Arrays of SQUIDsensorers can provide spatial information, while integrated low-noise readout electronics and vibration isolation improve performance. Most implementations require cooling to cryogenic temperatures and magnetic shielding.

Sensitivity and bandwidth vary, but optimized systems achieve noise levels on the order of a few femtoTesla per root Hertz, with bandwidth from a few Hz up to a few kHz for biomagnetic and materials studies. The dynamic range and temperature stability are important factors; calibration against known reference fields is standard practice.

Applications include magnetoencephalography (MEG), geophysical prospecting, nondestructive evaluation, and fundamental studies of magnetic materials and nanoparticle dynamics. The technology is also considered for precision control in quantum information experiments where magnetic field stabilization is critical.

Limitations include the need for cryogenic cooling, bulky shielding requirements, and high production and maintenance costs. Field deployment often requires specialized facilities and procedures for safety and performance verification.

See also: SQUID, biomagnetism, superconductivity.