SIM - a SuFET based induction magnetometer

Abstract

An attempt to generalize the current knowledge of passive magnetic field (MF) transducers - SQUID and induction sensors (IS) (MAFCOPS) - and to incorporate elements of both designs in order to find a way to improve their performance data (PD) by creating, in theory, a combined transducer-superconducting induction magnetometer (SIM). State-of-the-art of IS design is shown with two modifications for application in outer space - LF with sensitivity threshold (ST) 5 pT//spl radic/Hz-5 fT//spl radic/Hz in frequency range (FR) 20 Hz-16 kHz and HF with ST 0.5 pT/spl radic/Hz-1 fT//spl radic/Hz in FR 10 kHz-10 MHz. The superconducting field-effect transistor (SuFET) is incorporated into a wide-band IS device in order to acquire a ST below 1 fT//spl radic/Hz in the FR from small values of hertz to tens of MHz (0.1-10/sup 7/ Hz). The proposed magnetometer circuit consists of both room-temperature or cooled (up to superconductive) pickup coil (PC) and a SuFET. Both the TF and the ST for SIM are analytically investigated proceeding from the equivalent and noise circuit respectively. The sensitivity improvement of some SIM variants is shown in comparison with other state-of-the-art MAFCOPS. Constructional and operational distinctions of the designed sensor are explained.