Deconvolution of sinusoidal rapid EPR scans

Abstract

In rapid scan EPR the magnetic field is scanned through the signal in a time that is short relative to electron spin relaxation times. Previously it was shown that the slow scan lineshape could be recovered from triangular rapid scans by Fourier deconvolution. In this paper a general Fourier deconvolution method is described and demonstrated to recover the slow scan lineshape from sinusoidal rapid scans. Since an analytical expression for the Fourier transform of the driving function for a sinusoidal scan was not readily apparent, a numerical method was developed to do the deconvolution. The slow scan EPR lineshapes recovered from rapid triangular and sinusoidal scans are in excellent agreement for lithium phthalocyanine, a trityl radical, and the nitroxyl radical, tempone. The availability of a method to deconvolute sinusoidal rapid scans makes it possible to scan faster than is feasible for triangular scans because of hardware limitations on triangular scans.

Rapid-scan EPR of immobilized nitroxides

“…The incident powers were converted to B 1 using the known resonator efficiency of about $3.8\mathrm{normalG}/\sqrt{\mathrm{W}}$ at Q of 9000 [5]. For signal-to-noise calculations rapid scan signals were deconvolved into EPR absorption spectra and processed as described in [11,12]. Figures 2 - 4 compare CW and rapid scan spectra measured at powers optimized for each measurement.…”

“…The rapid-scan signals were deconvolved and background corrected [11,12]. The resulting spectra are the sum of up-field and down-field scans for the absorption and dispersion signals.…”

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters <em>In Vivo</em>

“…In this case the transfer is necessary because the program to process raw data (Matlab) is not on the same computer which has data collection software. The deconvolution algorithm which processes raw data is described in 29 .…”

Digitally generated excitation and near-baseband quadrature detection of rapid scan EPR signals

“…This allows filtering out the non-EPR component, which otherwise would overwhelm the digitizer, without compromising the absorption and dispersion components of the EPR signal. The approach is general for CW, multiharmonic [10], and rapid scan EPR [8, 11, 12] because these all involve periodic signals. For conventional CW the only frequency of interest is the modulation frequency, ω mod , for which the amplitude would be found for each field position in the spectrum.…”