# US 10,310,027 B2 · Systems and methods for detecting current using a kinetic inductance magnetic current imager > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,310,027 B2 - Document ID: US10310027B2 - Status: Granted - Kind: B2 - Application number: 15/625,652 - Filed: 2017-06-16 - Published: 2019-01-17 - Granted: 2019-06-04 - Earliest claimed: 2017-06-16 - Assignees: The Aerospace Corporation - Applicants: The Aerospace Corporation - Inventors: Robert H. Nelson - Web page: https://patentgrep.com/patent/US10310027B2 ## CPC - G01R 33/0354: {SQUIDS} - G01R 15/18: using inductive devices, e.g. transformers - G01R 15/20: using galvano-magnetic devices, e.g. Hall-effect devices {, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices} - G01R 31/2601: {Apparatus or methods therefor (G01R31/2607, G01R31/2642 take precedence)} - G01R 33/035: using superconductive devices - H01F 6/04: Cooling - H01F 6/06: Coils, e.g. winding, insulating, terminating or casing arrangements therefor - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract Under one aspect, a method for characterizing current of an operating device under test (DUT) includes injecting a signal into a superconducting sensor; determining a property of the superconducting sensor based on the injected signal; disposing the superconducting sensor in spaced relationship to the operating DUT; inducing a magnetic field in the superconducting sensor based on the spaced relationship, the current of the operating DUT, and the injected signal; determining a change in the property of the superconducting sensor resulting from the induced magnetic field; and estimating current of the operating DUT based on the change in the property of the superconducting sensor. ## Claims ### Claim 1 A method for characterizing current of an operating device under test (DUT), the method comprising: injecting a signal into a superconducting sensor; determining a property of the superconducting sensor based on the injected signal; disposing the superconducting sensor in spaced relationship to the operating DUT; inducing a magnetic field in the superconducting sensor based on the spaced relationship, the current of the operating DUT, and the injected signal; determining a change in the property of the superconducting sensor resulting from the induced magnetic field; and estimating current of the operating DUT based on the change in the property of the superconducting sensor. ### Claim 2 (depends on 1) The method of claim 1, further comprising scanning, via two-dimensional movement of a stage, the operating DUT with the superconducting sensor. ### Claim 3 (depends on 1) The method of claim 1, wherein the property comprises at least one of a quality factor, a resonant frequency, and a capacitance. ### Claim 4 (depends on 1) The method of claim 1, wherein the determining the property comprises: measuring a forward gain of the superconducting sensor; determining a resonant frequency based on the measured forward gain; determining a quality factor and a capacitance based on the determined resonant frequency; and determining a magnitude of the induced magnetic field based on the determined resonant frequency, the determined quality factor, and the determined capacitance. ### Claim 5 (depends on 1) The method of claim 1, wherein the superconducting sensor comprises a resonant circuit defined in a superconducting film. ### Claim 6 (depends on 5) The method of claim 5, wherein the resonant circuit includes an interdigitated capacitor and an inductor electrically coupled in parallel. ### Claim 7 (depends on 1) The method of claim 1, wherein the superconducting sensor is capacitively coupled to a transmission line transporting the injected signal. ### Claim 8 (depends on 1) The method of claim 1, wherein the injected signal comprises a broadband radio frequency range. ### Claim 9 (depends on 1) The method of claim 1, further comprising disposing the operating DUT in a vacuum chamber at a nominal operating temperature of the operating DUT. ### Claim 10 (depends on 7) The method of claim 7, wherein another superconducting sensor is capacitively coupled to the transmission line in parallel with the superconducting sensor. ### Claim 11 (depends on 10) The method of claim 10, further comprising multiplexing a collective output current of the superconducting sensor and the another superconducting sensor. ### Claim 12 A system for characterizing current of an operating device under test (DUT), the system comprising: a superconducting sensor; a cryocooler configured to dispose the superconducting sensor in spaced relationship to the operating DUT, the spaced relationship inducing a magnetic field in the superconductor sensor; a vacuum chamber enclosing the superconducting sensor and the operating DUT; and a controller configured to: inject a signal into the superconducting sensor; determine a property of the superconducting sensor based on the injected signal; determine a change in the property of the superconducting sensor resulting from the induced magnetic field; and estimate current of the operating DUT based on the change in the property of the superconducting sensor, wherein the induced magnetic field is based on the spaced relationship, current of the operating DUT, and the injected signal. ### Claim 13 (depends on 12) The system of claim 12, wherein the controller is further configured to scan, via two-dimensional movement of a stage, the operating DUT with the superconducting sensor. ### Claim 14 (depends on 12) The system of claim 12, wherein the property comprises at least one of a quality factor, a resonant frequency, and a capacitance. ### Claim 15 (depends on 12) The system of claim 12, wherein the superconducting sensor comprises a resonant circuit defined in a superconducting film. ### Claim 16 (depends on 12) The system of claim 12, wherein the resonant circuit includes an interdigitated capacitor and an inductor electrically coupled in parallel. ### Claim 17 (depends on 12) The system of claim 12, wherein the superconducting sensor is capacitively coupled to a transmission line transporting the injected signal. ### Claim 18 (depends on 12) The system of claim 12, wherein the injected signal comprises a broadband radio frequency range. ### Claim 19 (depends on 12) The system of claim 12, wherein the controller is further configured to dispose the operating DUT in a vacuum chamber at a nominal operating temperature of the operating DUT. ### Claim 20 (depends on 17) The system of claim 17, wherein another superconducting sensor is capacitively coupled to the transmission line in parallel with the superconducting sensor. ### Claim 21 (depends on 12) The system of claim 12, where the controller is further configured to multiplex a collective output current of the superconducting sensor and the another superconducting sensor.