An NMR marginal oscillator for measuring magnetic fields below 50 mT

Weyand, K.

doi:10.1109/19.192317

Cited by 17 publications

(8 citation statements)

References 5 publications

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“…The same concept can be found for a low field magnetometer presented by Weyand [34], which is shown in Figure 14, where a pair of back to back varicap diodes are substituted for the original tuning capacitors on the tank circuit allowing for a greater range of tuning and also for accurate tuning at field below 50 mT, which are typically challenging to measure. Varicap diodes are however challenging to work with and do not allow for as wide a tuning range as desired for maximum convenience.…”

Section: Oscillator Circuits Using Frequency Sweepmentioning

confidence: 91%

Advances in Electronics Prompt a Fresh Look at Continuous Wave (CW) Nuclear Magnetic Resonance (NMR)

2017

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Continuous Wave Nuclear Magnetic Resonance (CW-NMR) was a popular method for sample interrogation at the birth of magnetic resonance but has since been overlooked by most in favor of the now more popular pulsed techniques. CW-NMR requires relatively simple electronics although, for most designs, the execution is critical to the successful implementation and sensitivity of the system. For decades there have been reports in the literature from academic groups showing the potential of magnetic resonance relaxation time measurements in industrial applications such as the production of food and drink. However, the cost, complexity and power consumption of pulsed techniques have largely consigned these to the literature. Advances in electronics and developments in permanent magnet technology now require a fresh look at CW-NMR to see if it is capable of providing cost effective industrial solutions. In this article, we review the electronics that are needed to undertake a continuous wave NMR experiment starting with early designs and journeying through the literature to understand the basic designs and limitations. We then review the more recent developments in this area and present an outlook for future work in the hope that more of the scientific community will take a fresh look at CW-NMR as a viable and powerful low-cost measurement technique.

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Section: Oscillator Circuits Using Frequency Sweepmentioning

confidence: 91%

Advances in Electronics Prompt a Fresh Look at Continuous Wave (CW) Nuclear Magnetic Resonance (NMR)

2017

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“…The low field intensity calibration relies upon the application of the reference Garrett coil [1]. The best estimate of its constant at T ¼ 23 C, resulting from the intercomparison, is k H ¼ 2:023763 mT=A and its temperature dependence is exactly known.…”

Section: Realization Of the Reference Systemmentioning

confidence: 99%

“…It is the duty of the National Metrological Laboratories (NMLs) to ensure traceability and disseminate the units to the users by developing such standards [1]. These are either physical artifacts or specific experiments, which sustain tight calibration schedules and interlaboratory comparisons.…”

Section: Introductionmentioning

confidence: 99%

A reference system for the measurement of low-strength magnetic flux density

Fiorillo

Durin

Rocchino

2006

Journal of Magnetism and Magnetic Materials

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“…CW‐NMR has not been a particularly active topic of research for more than 50 years due to the advantages of pulsed NMR for measuring relaxation times. Some interest in the electronic development, in particular the development of oscillator circuits, has taken place, and CW‐NMR is used as the basis of sensitive magnetometers . CW‐NMR has also enjoyed some success as an imaging tool for use on samples with very short T 2 relaxation times .…”

Section: Introductionmentioning

confidence: 99%