| Zugriffsnummer | 32377 |
| Dokumenttyp | Zeitschriftenartikel |
| Sprache | Englisch |
| Titel | Integrated DC SQUID magnetometer with high dV/dB |
| Autor(in); Institution |
Drung, Dietmar; 9.33, Kryoelektronik, PTB-Berlin
Cantor, Robin; 9.52, Biomagnetismus, PTB-Berlin
Peters, M.; not affiliated
Ryhänen, T.; Metrology Research Institute, Helsinki University of Technology and Technical Research Centre of Finland, Espoo, FINLAND
Koch, Hans; 9.33, Kryoelektronik, PTB-Berlin
|
| Quelle/Jahr | IEEE Transactions on Magnetics: 27 (1991), 2, 3, 3001 - 3004 |
| ISSN | 0018-9464 (PRINT) ; 1941-0069 (ONLINE) |
| DOI | |
| Verlag | New York, NY: IEEE |
| Freie Schlagworte | SQUIDs ; electron device noise ; magnetometers ; niobium ; silicon compounds ; white noise |
| Zusammenfassung | A directly coupled DC SQUID magnetometer with very simple feedback electronics is presented. The magnetometer has been integrated on a 7.2×7.2 mm2 chip and fabricated using a four-level Nb/SixNy/Nb process. Eight pickup loops are connected in parallel to directly form the SQUID inductance of about 0.4 nH which leads to a high sensitivity B/Φ=0.47 nT/Φ0. An additional positive feedback (APF) circuit on the magnetometer chip has been used to increase the gradient of the V-Φ characteristic to dV/dΦ≃300 μV/Φ0 at the SQUID operating point. The resulting gradient of the transfer function dV/dB≃640 μV/nT makes it possible to directly readout the SQUID without helium-temperature impedance matching circuits or flux modulation techniques. Using a highly simplified feedback electronics consisting of an ultra-low-noise bipolar preamplifier and an integrator on a 10-cm2 PC board, a white noise level below 3 fT/√Hz with a 1/f corner frequency around 3 Hz, a 3-dB bandwidth of about 40 kHz, and a maximum feedback range of ±32 nT for frequencies up to 300 Hz have been measured. |
