LABORATORI NAZIONALI DI LEGNARO
Superconducting Quantum Interference Devices (SQUIDs) are the most sensitive sensors of magnetic flux. The smallest change in energy which the dc SQUID can detect in a bandwidth of 1 Hz, its energy resolution, achieves nowadays typical values of 10^(-31) J/Hz for commercial sensors operated at 4 K and 3x10^(-33) J/Hz at 100mK, about a factor 30 from the quantum limit. In principle, SQUIDs can measure all the physical quantities which can be transformed into magnetic flux, such as currents, voltages or displacements. Therefore, thanks to the user-friendliness of the modern cryogenic systems, SQUIDs can play an essential role in a large variety of applications in fundamental science, medical and industrial measurements. After an introduction on the working principle of the dc SQUID and its noise characteristics, I describe some of the most important applications with emphasis on those that are interesting for INFN.

DATA: 23-04-2013