Superconducting quantum magnetometer of the DC SQUID type

The measurement is discussed of very weak magnetic fields on the basis of the principle of Josephson effect. The detector is described of a superconducting quantum magnetometer which consists of a superconducting ring into which are inserted two parallel-connected Josephson junctions (DC SQUID detector). The calculation of the critical current of the detector and the determination of the output voltage of the detector are discussed. The principle is explained of the operation of the magnetometer and data are given on its present state and future development. (author)