Patent ID: 6154026
Filing Date: 2000-11-28
Classification: G01R,Y10S

Abstract:
A gradiometer for measuring a gradient of a magnetic field, comprising:a. a magnetometer having a magnetometer pickup loop with an area A.sub.m and an inductance L.sub.m ; andb. a flux transformer wherein the flux transformer comprisesi. a flux transformer input loop with an area A.sub.i and an inductance L.sub.i formed from a first superconducting material, wherein the flux transformer input loop is inductively coupled to the magnetometer pick up loop; andii. a flux transformer pickup loop having an area A.sub.p and an inductance L.sub.p formed from a second superconducting material and electrically connected to the flux transformer input loop such that a current induced in the flux transformer by any magnetic field is directed in the same direction in both the input loop and pickup loops of the flux transformer, and further, wherein the areas and inductances of the magnetometer pickup loop and flux transformer input loop and pickup loop are selected such that the equation.alpha.=[A.sub.m /(A.sub.p +A.sub.i)](L.sub.p +L.sub.i)/(L.sub.i L.sub.m).sup.1/2is satisfied, where a is equal to M.sub.i /(L.sub.i L.sub.m).sup.1/2 and M.sub.i is the mutual inductance between the magnetometer pickup loop and the flux transformer input loop.