Document Type

Article

Language

eng

Publication Date

1-2017

Publisher

Elsevier

Source Publication

Journal of Magnetic Resonance

Source ISSN

1090-7807

Original Item ID

DOI: 10.1016/j.jmr.2016.11.014

Abstract

In continuous-wave (CW) Electron Paramagnetic Resonance (EPR) a low-frequency time-harmonic magnetic field, called field modulation, is applied parallel to the static magnetic field and incident on the sample. Varying amplitude of the field modulation incident on the sample has consequences on spectral line-shape and line-height over the axis of the sample. Here we present a method of coupling magnetic field into the cavity using slots perpendicular to the sample axis where the slot depths are designed in such a way to produce an axially uniform magnetic field along the sample. Previous literature typically assumes a uniform cross-section and axial excitation due to the wavelength of the field modulation being much larger than the cavity. Through numerical analysis and insights obtained from the eigenfunction expansion of dyadic Green’s functions, it is shown that evanescent standing-wave modes with complex cross-sections are formed within the cavity. From this analysis, a W-band (94 GHz) cylindrical cavity is designed where modulation slots are optimized to present a uniform 100 kHz field modulation over the length of the sample.

Comments

Accepted version. Journal of Magnetic Resonance, Vol. 274 (January 2017): 115-124. DOI. © 2016 Elsevier Inc. Used with permission.

Download

Share

COinS