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TT: Fachverband Tiefe Temperaturen

TT 12: Symposium: Cryodetectors and SQUID

TT 12.8: Vortrag

Dienstag, 26. Februar 2008, 12:30–12:45, H 0104

Highly sensitive and easy-to-use SQUID sensors — •Frank Ruede^1,2, Cornelia Aßmann¹, Jörn Beyer¹, Dietmar Drung¹, Alexander Kirste¹, Margret Peters¹, and Thomas Schurig¹ — ¹PTB, Berlin, Germany — ²Magnicon GbR, Hamburg, Germany

We have developed a family of low-noise superconducting quantum interference devices (SQUIDs) to cover a wide range of applications. These sensors are robust and easy to use without compromising noise performance. They are optimized for operation with the Magnicon high-speed flux-locked loop (FLL) electronics XXF-1.

This contribution focuses on SQUID current sensors with higher input inductances of up to 2μH. Typical applications for these sensors are the measurement of the magnetic field with a superconducting pickup loop connected to the input coil.

Dependent on the required noise level, single-stage and two-stage devices were realized in our latest sensor family 'C5'. The single-stage sensors achieve a coupled energy resolution around 70 times Planck's constant h at 4,2K and the two-stage sensor of 45h. They consist of a single front-end SQUID which is read out by a 16-SQUID series array. These sensors are very convenient to use as their voltage-flux characteristic is essentially single-SQUID-like. Devices optimized for low temperature operation achieve typically 4h at 300mK.

All sensor designs have an optional integrated current limiter (Q-spoiler) in series to the input coil, which can be used to reduce the current in pulsed applications like magnetorelaxometry.