Squid magnetometer including a flux-gate chopper using a mechanically vibrating superconducting mirror
First Claim
1. An apparatus for measuring low frequncy magnetic fields with a SQUID magnetometer having a super-conducting flux transformer for coupling measurement signals into a sensor comprising a direct current SQUID, comprising:
- a flux transformer element being associated with at least first and second inductively coupled windings of the super-conducting flux transformer, the inductively coupled windings enclosing a common coupling hole;
a first carrier element for supporting at least one of the inductively coupled windings;
a second carrier element attached to the first carrier element;
said second carrier element comprisinga super-conducting oscillating mirror having an oscillating diaphragm coated with super-conducting material attached to the second carrier element; and
means for changing an effective size of the coupling hole and thereby a mutual inductance of the coupled windings by means of the super-conducting vibrating mirror at a modulation frequency lying in a low-level noise frequency range that is characteristic of the SQUID.
1 Assignment
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Accused Products
Abstract
An apparatus for measuring magnetic fields that change at extremely low frequency contains a SQUID magnetometer having a super-conducting flux transformer for inductively coupling the measuring signal into a direct current SQUID sensor. Quasi-static magnetic fields that have frequencies far below 1 Hz are detected. The flux transformer has two inductively coupled windings. At least one winding is arranged on a first carrier element (chip) that enclose a common coupling hole. A second carrier element (counter chip) is attached to the first carrier element. A super-conducting oscillating diaphragm is positioned opposite the coupling hole. The mutual inductance of the windings is modulated with this super-conducting vibrating diaphragm through appropriate changes of the effective size of the coupling hole with a frequency that lies in a characteristic frequency range for low-level noise operation of the SQUID.
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Citations
10 Claims
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1. An apparatus for measuring low frequncy magnetic fields with a SQUID magnetometer having a super-conducting flux transformer for coupling measurement signals into a sensor comprising a direct current SQUID, comprising:
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a flux transformer element being associated with at least first and second inductively coupled windings of the super-conducting flux transformer, the inductively coupled windings enclosing a common coupling hole; a first carrier element for supporting at least one of the inductively coupled windings; a second carrier element attached to the first carrier element; said second carrier element comprising a super-conducting oscillating mirror having an oscillating diaphragm coated with super-conducting material attached to the second carrier element; and means for changing an effective size of the coupling hole and thereby a mutual inductance of the coupled windings by means of the super-conducting vibrating mirror at a modulation frequency lying in a low-level noise frequency range that is characteristic of the SQUID. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification