A magnetic current sensor with SQUID readout |
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| Luca Callegaro, Bruno Trinchera, Luca Roncaglione |
- Abstract:
- A cryogenic magnetic current sensor has been constructed and tested for operation and sensitivity in the ac regime. The sensor is based on a ferromagnetic-core current transformer, coupled to a superconducting-quantum-interferencedevice (SQUID) current detector. The SQUID electronics provides a voltage output that can be coupled to roomtemperature signal recovery electronics, such as a lock-in amplifier. Working in liquid helium (4.2K) the sensor transresistance is about 1.8M in the audio frequency range; the equivalent input current noise of the sensor, at the frequency of 1 kHz, is a few pAHz−1/2 per unit primary winding turn. A major contribution to the detector noise is the thermal noise of the ferromagnetic core; however, an important excess noise contribution at low frequency is also present. The experiment is intended as a feasibility test towards the realization of high-sensitivity electromagnetic devices, such as current comparators, to be employed in primary current and impedance metrology setups working in the audio frequency range.
- Keywords:
- SQUID; current sensor; current detector; current comparator; current transformer
- Download:
- IMEKO-TC4-2014-211.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC4
- Event name:
- TC4 Symposium 2014
- Title:
20th IMEKO TC4 Symposium on Measurements of Electrical Quantities (together with 18th TC4 International Workshop on ADC and DCA Modeling and Testing, IWADC)
"Research on Electrical and Electronic Measurement for the Economic Upturn"- Place:
- Benevento, ITALY
- Time:
- 15 September 2014 - 17 September 2014