| 摘要 |
PURPOSE:To detect an external magnetic signal by connecting a resistor having a resistance of a sufficiently smaller value than a resistance value R of a shunt resistance, in parallel to a Josephson junction, and detecting a current shunted to its resistor. CONSTITUTION:A constant-current is made to flow between a terminal 3 and a ground by a constant-current circuit to the first DC SQUID21, and a constant- current is made to flow between a terminal and a ground by the constant- current circuit to the second DC SQUID22. A resistance value of a resistor 10 connected in parallel to the DC SQUID21 is made sufficiently smaller than R. An inductance 11 connected in series to the resistor 10 is coupled with an inductance loop 2 of the DC SQUID22. By a current DELTAI flowing to the inductance 11, a current of (n).DELTAI flows to the inductance loop 2 of the DC SQUID22. Therefore, when an inductance value of the inductance loop of the DC SQUID22 is denoted as LB, a magnetic flux of (n)DELTAI.LB is induced in the loop. |
