A linear magnetic field scan driver

Quine, Richard W.; Czechowski, Tomasz; Eaton, Gareth R.

doi:10.1002/cmr.b.20128

Cited by 25 publications

(21 citation statements)

References 32 publications

(47 reference statements)

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“…The simplest deconvolution procedure is for responses to linear (triangular) field scans [5], but linear scans are the most demanding of the driver [26]. The driver needs a feedback system to create a linearly changing current, not voltage, across the coils.…”

Section: Instrumentation For Rapid Scansmentioning

confidence: 99%

Rapid-scan EPR imaging

Eaton

Shi

Woodcock

et al. 2017

Journal of Magnetic Resonance

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In rapid-scan EPR the magnetic field or frequency is repeatedly scanned through the spectrum at rates that are much faster than in conventional continuous wave EPR. The signal is directly-detected with a mixer at the source frequency. Rapid-scan EPR is particularly advantageous when the scan rate through resonance is fast relative to electron spin relaxation rates. In such scans, there may be oscillations on the trailing edge of the spectrum. These oscillations can be removed by mathematical deconvolution to recover the slow-scan absorption spectrum. In cases of inhomogeneous broadening, the oscillations may interfere destructively to the extent that they are not visible. The deconvolution can be used even when it is not required, so spectra can be obtained in which some portions of the spectrum are in the rapid-scan regime and some are not. The technology developed for rapid-scan EPR can be applied generally so long as spectra are obtained in the linear response region. The detection of the full spectrum in each scan, the ability to use higher microwave power without saturation, and the noise filtering inherent in coherent averaging results in substantial improvement in signal-to-noise relative to conventional continuous wave spectroscopy, which is particularly advantageous for low-frequency EPR imaging. This overview describes the principles of rapid-scan EPR and the hardware used to generate the spectra. Examples are provided of its application to imaging of nitroxide radicals, diradicals, and spin-trapped radicals at a Larmor frequency of ca. 250 MHz.

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Section: Instrumentation For Rapid Scansmentioning

confidence: 99%

Rapid-scan EPR imaging

Eaton

Shi

Woodcock

et al. 2017

Journal of Magnetic Resonance

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“…Deconvolution of the rapid scan signals results in the conventional slow scan absorption and dispersion signals. Several papers provide the background on rapid scan EPR (Harbridge et al, 2002; Joshi et al, 2005; Quine et al, 2009; Quine et al, 2010; Stoner et al, 2004; Tseitlin et al, 2009). …”

Section: Introductionmentioning

confidence: 99%

Comparison of continuous wave, spin echo, and rapid scan EPR of irradiated fused quartz

Mitchell

Quine

Tseitlin

et al. 2011

Radiation Measurements

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The E′ defect in irradiated fused quartz has spin lattice relaxation times (T1) about 100 to 300 μs and spin-spin relaxation times (T2) up to about 200 μs, depending on the concentration of defects and other species in the sample. These long relaxation times make it difficult to record an unsaturated continuous wave (CW) electron paramagnetic resonance (EPR) signal that is free of passage effects. Signals measured at X-band (~9.5 GHz) by three EPR methods: conventional slow-scan field modulated EPR, rapid scan EPR, and pulsed EPR, were compared. To acquire spectra with comparable signal-to-noise, both pulsed and rapid scan EPR require less time than conventional CW EPR. Rapid scan spectroscopy does not require the high power amplifiers that are needed for pulsed EPR. The pulsed spectra, and rapid scan spectra obtained by deconvolution of the experimental data, are free of passage effects.

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“…Rapid-scan signals were obtained on a Bruker E500T X-band spectrometer with a Bruker Flexline ER4118X-MD5 dielectric resonator as described in [8]. Rapid magnetic field scans were generated with scan drivers similar to those described previously [9, 10]. Signals were acquired with a Bruker SpecJetII fast digitizer.…”

Section: Methodsmentioning

confidence: 99%

Rapid-scan coherence signals in X-band EPR spectra of semiquinones with small hyperfine splittings

Elajaili

Rinard

et al. 2015

Journal of Magnetic Resonance

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Rapid-scan EPR signals for semiquinones with very-small well-resolved hyperfine splittings exhibit coherence signals at a time after passing through the EPR line that is proportional to the reciprocal of the hyperfine splitting. Such coherences are a general phenomenon due to constructive interference of the responses to transient excitation of spins by rapid scan of the magnetic field across equally spaced spin packets. Examples are shown for 2,3,5,6-tetramethoxy-1,4-benzosemiquinone with aH = 46 mG for 12 protons and for 2,5-di-t-butyl-1,4-benzosemiquinone with aH = 59 mG for 18 protons.

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A linear magnetic field scan driver

Cited by 25 publications

References 32 publications

Rapid-scan EPR imaging

Rapid-scan EPR imaging

Comparison of continuous wave, spin echo, and rapid scan EPR of irradiated fused quartz

Rapid-scan coherence signals in X-band EPR spectra of semiquinones with small hyperfine splittings

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