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US5546000A
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Method for the reduction of radiation damping during signal acqusition in NMR experiments
Assignee: Bruker Biospin Corp
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Filing: 1995-03-24
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Granted: 1996-08-13
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Expires: 2015-03-24
Abstract
Abstract A method of reducing radiation damping during free induction decay in NMR measurements of samples having a narrow line width uses the active switching of the quality factor value of the coil circuit of an NMR detection probe. After application of an excitation pulse to the sample, data acquisition is accomplished in periodic samples. The Q of the coil circuit is set to a high value while each sample is being taken, but is reduced significantly in between samples by detuning the coil circuit. Minimization of the high-Q state of the coil circuit and maximization of the difference between the high Q value and the low Q value greatly decrease the detrimental effects of radiation damping on free induction decay. The coil circuit Q is modified automatically by the application of a Q switching signal generated by a controller, such as a computer which controls other aspect of the NMR experiment.
Inventors
- 👤 Werner E. Maas
- 👤 David G. Cory
- 👤 Frank H. Laukien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:43
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/36; G01R33/3671; G01R33/3628; G01R33/3621
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
121 words
A method of reducing the effect of radiation damping on free induction decay during an NMR measurement of a sample, the method comprising: providing an NMR probe having a coil circuit for which the quality factor changes between a high-Q state and a low-Q state in response to the application of a Q signal; exciting nuclei of interest in the sample; detecting a resonance signal of the nuclei of interest at selected sampling times during free induction decay following the excitation pulse; and applying the Q signal to the probe coil circuit such as to change the coil circuit to a high-Q state during the sampling times and change the coil circuit to a low-Q state in between the sampling times.
Claim 2
Independent Claim
121 words
A method of reducing the effect of radiation damping on free induction decay during an NMR measurement of a sample, the method comprising: providing an NMR probe having a coil circuit for which the quality factor changes between a high-Q state and a low-Q state in response to the application of a Q signal; exciting nuclei of interest in the sample; detecting a resonance signal of the nuclei of interest at selected sampling times during free induction decay following the excitation pulse; and applying the Q signal to the probe coil circuit such as to change the coil circuit to a high-Q state during the sampling times and change the coil circuit to a low-Q state in between the sampling times.
Claim 3
Dependent Claim
30 words
A method according to claim 1 further comprising limiting characteristics of the sample such that a radiation damping time constant is shorter than the spin-spin relaxation time of the sample.
Claim 4
Dependent Claim
22 words
A method according to claim 1 wherein exciting the nuclei of interest comprises exciting the nuclei of interest with an excitation pulse.
Claim 5
Dependent Claim
27 words
A method according to claim 3 wherein the excitation pulse is one of a train of excitation pulses which are used to excite the nuclei of interest.
Claim 6
Dependent Claim
28 words
A method according to claim 1 wherein detecting a resonance signal further comprises detecting resonance signals in multiple dimensions during a detection period of a multi-dimensional NMR experiment.
Claim 7
Dependent Claim
30 words
A method according to claim 1 wherein applying the Q signal to the probe coil circuit comprises applying the Q signal to the probe coil circuit automatically with a controller.
Claim 8
Dependent Claim
46 words
A method according to claim 6 wherein applying the Q signal to the probe coil circuit further comprises applying the Q signal to the probe coil circuit with a controller that comprises a data processor and which controls additional NMR components used in performing the measurement.
Claim 9
Dependent Claim
26 words
A method according to claim 1 wherein detecting a resonance signal of the nuclei of interest at selected times further comprises detecting the resonance signal periodically.
Claim 10
Dependent Claim
44 words
A method according to claim 1 further comprising adjusting the Q signal such that the low-Q state and the high-Q state of the probe coil circuit are balanced to provide a substantial reduction in radiation damping without an inordinate increase in detected signal noise.
Claim 11
Independent Claim
156 words
A method of reducing the effect of radiation damping on free induction decay during an NMR measurement of the resonance signals of nuclei of interest contained in a sample for which a radiation damping time constant is shorter than the spin-spin relaxation time of the sample, the method comprising: providing an NMR probe having a coil circuit for which the quality factor changes between a high-Q state and a low-Q state in response to the application of a Q signal; exciting the nuclei of interest in the sample with an excitation pulse; periodically detecting a resonance signal of the nuclei of interest at predetermined times during free induction decay following the excitation pulse; and applying the Q signal to the probe coil circuit with a controller such as to automatically change the coil circuit to a high-Q state during the sampling times and change the coil circuit to a low-Q state in between the sampling times.
Claim 12
Independent Claim
156 words
A method of reducing the effect of radiation damping on free induction decay during an NMR measurement of the resonance signals of nuclei of interest contained in a sample for which a radiation damping time constant is shorter than the spin-spin relaxation time of the sample, the method comprising: providing an NMR probe having a coil circuit for which the quality factor changes between a high-Q state and a low-Q state in response to the application of a Q signal; exciting the nuclei of interest in the sample with an excitation pulse; periodically detecting a resonance signal of the nuclei of interest at predetermined times during free induction decay following the excitation pulse; and applying the Q signal to the probe coil circuit with a controller such as to automatically change the coil circuit to a high-Q state during the sampling times and change the coil circuit to a low-Q state in between the sampling times.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-08-13 | 2000-02-12 | 2000-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-13 | 2004-02-12 | 2004-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-08-13 | 2008-02-12 | 2008-08-13 | $7700.00 | Window Closed / Lapsed |