Tesla/volt calibration method for integrated planar SQUID gradiometers

A calibration method for integrated planar SQUID gradiometers is proposed based on a spatial Fourier technique and on the fact that each gradiometer design has its own theoretical spatial transfer function. The calibration consists in scanning the gradiometer over a known input field source and measuring the output voltage values. The measured transfer function is the result of the division of the Fourier transform of the output signal by the Fourier transform of the input signal. The calibration factor is obtained by fitting the measured transfer function with the theoretical one. The experimental procedure was simulated and calibration factors with imprecision of about 0.2% are expected in actual measurements.