PURPOSE: To improve sensitivity of a SQUID magnetic flux meter by providing a shelding means between a transmission line of feedback modulation signal and other signal lines among the wirings and connectors for connectors for connecting the DC SQUID and an FLL circuit device.
CONSTITUTION: Two shield tubes 1 for wiring are arranged in an external pipe 5 of probe. One of them shields a shield wire 2 for the feedback modulation signal, and another one has the structure to shield a shield wire 3 for a bias current and a shield wire 4 for a magnetic flux voltage. A niobium (Nb) is used for the material of shield tube 1 but other superconducting materials can be also used. With the above-mentioned structure, an electromagnetic noise generated from the feedback modulation signal line is prevented from becoming a noise for other signals, then the noise of DC SQUID magnetic flux meter is reduced and the sensitivity can be improved.
SHIMIZU NOBUHIRO
KAYANE KAZUO
GOTO KOICHI
