Substance detection by nuclear quardrupole resonance using at least two different excitation frequencies
US6900633B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 28, 2002 |
| Grant date | May 31, 2005 |
| Priority date | — |
| Expiry date | Jun 28, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/441
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
This invention involves an apparatus to measure the nuclear quadrupole (NQR) response of a specimen using three frequencies. Three-frequency NQR involves excitation of at least two transitions that causes an observed signal at a third transition frequency. Thus, the transition excited and detected is not irradiated at all. This reduces undesirable interfering signals due to the excitation, for example as a result of acoustic ringing and/or tank circuit ring-down, since the excitation is not applied at the frequency that is detected. This invention will be particularly useful to detect substances selected from the group consisting of explosives and narcotics using nitrogen NQR.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.