NMR probes can be tuned and matched on the bench or while in the magnet using a sweep generator and oscilloscope or a specialized tuning box such as the one available through Morris Instruments. More typically, probe tuning and matching are monitored using the electronics in the NMR console and preamplifier. In either case, it is important to realize that any filter or cable between the preamplifier and the probe is part of the rf circuit being tuned and should therefore be present while adjusting the tuning and matching capacitors of the probe. This is illustrated in the figure below. An NMR probe was tuned and matched using the wobble function of a Bruker AVANCE spectrometer. There was a bandpass filter and a short cable between the preamplifier and the probe. The tuning curve is shown in the top of the figure. The 90° pulse was measured at 11.25 ?sec. The short cable was then replaced with a long cable and the probe tuning and matching capacitors were left unchanged. The tuning curve is shown in the bottom of the figure below. It is clear that the overall circuit is no longer tuned and matched. The 90° pulse was measured at 13.75 ?sec using the long cable.
A 250 GHz Gyrotron with a 3 GHz Tuning Bandwidth for Dynamic Nuclear Polarization
A 250 GHz Gyrotron with a 3 GHz Tuning Bandwidth for Dynamic Nuclear Polarization
Publication year: 2012
Source:Journal of Magnetic Resonance</br>
Alexander B. Barnes, Emilio A. Nanni, Judith Herzfeld, Robert G. Griffin, Richard J. Temkin</br>
We describe the design and implementation of a novel tunable 250 GHz gyrotron oscillator with >10 W output power over most of a 3 GHz band and >35 W peak power. The tuning bandwidth and power are sufficient to generate a >1 MHz nutation frequency across the entire nitroxide EPR lineshape for cross effect DNP, as well as to...
nmrlearner
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03-30-2012 10:45 AM
[Question from NMRWiki Q&A forum] Tuning and matching problem on atma command
Tuning and matching problem on atma command
hello nmr wikier I am using Z-gradiant BBI probe on bruker AV-500 since last weak I am facing tuning and matching problem both by atma command and manually atmm command.ON atma command it is abroted in all standard sample and on atmm the coarse button did not arive only fine button active on proton channel while carbon channel work fine and befor reaching in mid of the curve the button reaches at end and curve goes away from center.I have tried by enlarging wbsw by 2o 40 60 but it is not working.I have also tried all command which are in BASH...
nmrlearner
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10-05-2011 08:57 PM
[U. of Ottawa NMR Facility Blog] Probe Tuning and 90 Degree Pulses
Probe Tuning and 90 Degree Pulses
In order to get meaningful results from multiple-pulse NMR pulse sequences, it is essential that the 90° and 180° pulses are calibrated at the power levels used in the sequences (see this post for example). The calibrations are usually done on a standard sample in a well tuned and matched probe. The calibrations are typically stored in a file which is called up when setting up particular NMR experiments. It is important to know that these calibrations are correct for the particular sample of interest only when the probe is well tuned and matched. For...
nmrlearner
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09-16-2011 10:02 PM
[Question from NMRWiki Q&A forum] Tuning probe failed after a dual probe was replaced with a BBI probe
Tuning probe failed after a dual probe was replaced with a BBI probe
We generally use Dual to run 13C and BBI to run 2D. After changed the probe, the command "edhead" was used to set the probe. Put the sample tube, lock the solvent, and then type "atma" to tune the probe. We always do it like this, but now we can not tune the proton after installed the BBI probe (13C is OK). The dip can not be found by "atma", and "atmm" was also not work on forming a dip. What is the most possible reason for this error? How to solve it and avoid it in the future ? Thanks. (Instrument: Bruker 400 MHz,...
nmrlearner
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08-23-2011 05:31 PM
Signal enhancement in protein NMR using the spin-noise tuning optimum
Signal enhancement in protein NMR using the spin-noise tuning optimum
Abstract We have assessed the potential of an alternative probe tuning strategy based on the spin-noise response for application in common high-resolution multi-dimensional biomolecular NMR experiments with water signal suppression on aqueous and salty samples. The method requires the adjustment of the optimal tuning condition, which may be offset by several 100 kHz from the conventional tuning settings using the noise response of the water protons as an indicator. Although the radio frequency-pulse durations are...
nmrlearner
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10-09-2010 03:03 AM
Signal enhancement in protein NMR using the spin-noise tuning optimum.
Signal enhancement in protein NMR using the spin-noise tuning optimum.
Signal enhancement in protein NMR using the spin-noise tuning optimum.
J Biomol NMR. 2010 Oct 6;
Authors: Nausner M, Goger M, Bendet-Taicher E, Schlagnitweit J, Jerschow A, Müller N
We have assessed the potential of an alternative probe tuning strategy based on the spin-noise response for application in common high-resolution multi-dimensional biomolecular NMR experiments with water signal suppression on aqueous and salty samples. The method requires the adjustment of the...
nmrlearner
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10-07-2010 10:33 AM
Pulse length/power level calculator
Pulse length/power level ? calculator
http://www.spectroscopynow.com/FCKeditor/UserFiles/File/specNOW/HTML%20files/pulselength.htm
Go to BMNRC community to find more info about this topic.
Cable Length and Probe Tuning
Linear Mode
