Variable Inductance Pick-Up Coil for Detection of Flux Trapped in a Loop
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
This article relates generally to the detection and measurement of magnetic fields and more particularly to the detection and measurement of magnetic fields using a variable inductance pick-up coil for the detection by a SQUID (Superconducting Quantum Interference Device) of flux trapped in a loop. Still more specifically, apparatus is provided which permits the detection of magnetic field passing through a loop and the readout by a SQUID magnetometer of flux trapped in a loop to be separated into two separate steps. SQUIDS are extremely sensitive detectors of changes in the flux passing through the SQUID loop. As shown in the above figure, a SQUID 1 having a loop L is typically inductively coupled to an input coil Li and a pick-up coil Lp connected in series. Optimal resolution occurs if LpZLi .