DEVELOPMENT OF HIGH TC-SUPERCONDUCTOR SQUID-BASED MAGNETOMETER

The present paper describes the design and development of a liquid nit rogen-cooled RF SQUID magnetometer made of high T(c) superconductor (H TS) Y-Ba-Cu-O ceramics. The cryogenic module, glass-reinforced plastic cryostat and HTS SQUID ensure stable performance at the sensitivity l evel of 2 x 10(-13)-4 x 10(-13) T Hz-1/2 over a period of one year. Th e service period of the system after a single nitrogen filling is abou t 10-12 days. A differential HTS magnetometer design is also described . The magnetic noise spectral density of this magnetometer was measure d in a shielded room consisting of two layers of commercially pure alu minium. It was shown that the use of this differential magnetometer de creased the contribution of variations in the environmental magnetic f ield to the output signal by 100 times. Magnetocardiographic traces we re obtained.