Inspection apparatus based on nuclear magnetic resonance
US4777443A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1987 |
| Grant date | Oct 11, 1988 |
| Priority date | — |
| Expiry date | Nov 12, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/0358
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed in a nuclear magnetic resonance (NMR) based inspection apparatus using an SQUID flux meter for detecting a small NMR signal, in which a receiving coil for receiving the NMR signal from an object is connected to a mixer, which mixes a reference high-frequency signal with the NMR signal so that the NMR signal is reduced to a low-frequency signal having a differential component of frequencies of both signals, and the low-frequency signal is applied to the input coil of the SQUID flux meter so that it is converted into a voltage signal. The mixer circuit includes Schottky diodes operative at a liquid helium temperature or Josephson junctions, and the portions of apparatus from the reception coil up to the SQUID flux meter are operated in a superconductive state at a liquid helium temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.