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Simultaneous measurement of ultra-low magnetic fields

Multi-channel readout electronics for novel SQUID sensor systems

PTBnews 1.2020
Especially interesting for

biomagnetic diagnostics



developers of superconducting sensor systems

Within the scope of an industrial cooperation project, PTB has developed new readout electronics for dc-SQUID multi-channel systems. They are highly scalable and flexible and allow up to several thousand channels to be read out simultaneously.

Readout electronics for dc-SQUID multichannel systems. In the foreground: 19’’ plug-in card with readout electronics for 9 sensor channels.

SQUIDs (superconducting quantum interference devices) are the world's most sensitive and accurate magnetic field detectors. They can be used to detect the extremely small changes in the magnetic fields that occur in the human heart or brain, but also to determine the properties of magnetic nanoparticles. Directly coupled dc-SQUIDs can also be used to read out other highly sensitive superconducting sensors. PTB is the world leader in the development of SQUIDs and readout electronics.

In recent years, there has been an increasing demand for electronics for measuring systems with a high number of superconducting sensors. In response to these market needs, PTB and Magnicon GmbH, in cooperation with the Institute of Applied Photonics e. V. Berlin, have developed readout electronics for dc-SQUID multi-channel systems. To make this system available to a wide range of users, the electronics are designed for a voltage white noise of 0.7 nV/Hz1/2, a maximum bandwidth of approx. 5 MHz and a current consumption of approx. 25 mA per channel. With this design, the compromise between the total current requirement of a fully equipped system and the required performance is acceptable for the intended measurements. For highly sensitive experiments, all microcontrollers can be put into sleep mode during measurements to avoid interferences. Up to three different galvanically decoupled signal lines are available to the user for asynchronous hardware control. This functionality is essential, e.g., in applications where the current in the superconducting sensors must be limited in time – as in experiments on LF-NMR (low-field nuclear magnetic resonance), MRI (magnetic resonance imaging) or relaxometry

The multi-channel electronics will enable new SQUID sensor systems to be operated at PTB and other institutions. The project was supported by Pro FIT, a program of the Investitionsbank Berlin (IBB) for the promotion of research, innovation and technology, and by the European Regional Development Fund.


Sylke Bechstein
Department 7.6
Cryogenic Sensors
Phone: +49 30 3481-7426
Opens window for sending emailsylke.bechstein(at)ptb.de

Scientific publication

S. Bechstein, D. Drung, M. Scheiner, F. Petsche, S. Ali Valiollahi, R. Körber, H. J. Barthelmess: Highly scalable readout electronics for large multichannel dc-SQUID systems. Accepted for publication in the proceedings of EUCAS 2019 Journal of Physics: Conference Series