The design and performance of a planar microwave rf-SQUID read out by a cryogenic HEMT preamplifier are described. The SQUID sensor consists of a planar half wavelength microstrip resonator, into which the SQUID-loop is integrated. The SQUID is operated at a pump frequency of 1.7 GHz. The cryogenic preamplifier employs a microwave HEMT, located close to the SQUID sensor. Measurements of the flux noise and the fractional step rise parameter a were carried out in the temperature range between 4.2 K and 1.5 K. In an open loop, a flux noise of 2 x 10(-6) Phi(0)/root HZ was measured at 4.2 K resulting in an energy resolution of about 100 h. The design of a 3 GHz magnetometer is also described and the preliminary results of the measurements are reported.
Improved Sensitivity of Planar Microwave Biased Rf-Squids using a Cryogenic Hemt Preamplifier / Fontana, G.; Mezzena, R.; Vitale, S.; Cerdonio, M.; Mmuck, M.; Hallmanns, G.; Heiden, C.. - In: IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY. - ISSN 1051-8223. - 3:1(1993), pp. 1820-1823. [10.1109/77.233328]
Improved Sensitivity of Planar Microwave Biased Rf-Squids using a Cryogenic Hemt Preamplifier
Fontana G.;Mezzena R.;Vitale S.;Cerdonio M.;
1993-01-01
Abstract
The design and performance of a planar microwave rf-SQUID read out by a cryogenic HEMT preamplifier are described. The SQUID sensor consists of a planar half wavelength microstrip resonator, into which the SQUID-loop is integrated. The SQUID is operated at a pump frequency of 1.7 GHz. The cryogenic preamplifier employs a microwave HEMT, located close to the SQUID sensor. Measurements of the flux noise and the fractional step rise parameter a were carried out in the temperature range between 4.2 K and 1.5 K. In an open loop, a flux noise of 2 x 10(-6) Phi(0)/root HZ was measured at 4.2 K resulting in an energy resolution of about 100 h. The design of a 3 GHz magnetometer is also described and the preliminary results of the measurements are reported.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione
