Aqueous sample in an EPR cavity: Sensitivity considerations

Yuri E. Nesmelov; Anand Gopinath; David D. Thomas

doi:10.1016/j.jmr.2003.12.005

Aqueous sample in an EPR cavity: Sensitivity considerations

Yuri E. Nesmelov, Anand Gopinath, David D. Thomas

Research output: Contribution to journal › Article › peer-review

22 Scopus citations

Abstract

The radial mode matching (RMM) method has been used to calculate accurately the microwave field distribution of the TE₀₁₁ mode in a spherical EPR cavity containing a linear aqueous sample, in order to understand in detail the factors affecting sensitivity in EPR measurements at X band. Specific details of the experiment were included in the calculations, such as the cavity geometry, the presence of a quartz dewar, the size of the aqueous sample, and the sample's dielectric properties. From the field distribution, several key physical parameters were calculated, including cavity Q, filling factor, mean microwave magnetic field at the sample, and cavity efficiency parameter Λ. The dependence of EPR signal intensity on sample diameter for a cylindrical aqueous sample was calculated and measured experimentally for non-saturated and half-saturated samples. The optimal aqueous sample diameter was determined for both cases. The impact of sample temperature, conductivity, and cavity Q on sensitivity of EPR is discussed.

Original language	English (US)
Pages (from-to)	138-146
Number of pages	9
Journal	Journal of Magnetic Resonance
Volume	167
Issue number	1
DOIs	https://doi.org/10.1016/j.jmr.2003.12.005
State	Published - Mar 2004

Bibliographical note

Funding Information:
This work was supported by NIH Grants AR32961 (D.D.T.), AR48961 (Y.N.), and fellowship of University of Minnesota Supercomputing Institute (Y.N.).

Keywords

Cavity
EPR
Field distribution
Sensitivity
Water

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title = "Aqueous sample in an EPR cavity: Sensitivity considerations",

abstract = "The radial mode matching (RMM) method has been used to calculate accurately the microwave field distribution of the TE011 mode in a spherical EPR cavity containing a linear aqueous sample, in order to understand in detail the factors affecting sensitivity in EPR measurements at X band. Specific details of the experiment were included in the calculations, such as the cavity geometry, the presence of a quartz dewar, the size of the aqueous sample, and the sample's dielectric properties. From the field distribution, several key physical parameters were calculated, including cavity Q, filling factor, mean microwave magnetic field at the sample, and cavity efficiency parameter Λ. The dependence of EPR signal intensity on sample diameter for a cylindrical aqueous sample was calculated and measured experimentally for non-saturated and half-saturated samples. The optimal aqueous sample diameter was determined for both cases. The impact of sample temperature, conductivity, and cavity Q on sensitivity of EPR is discussed.",

keywords = "Cavity, EPR, Field distribution, Sensitivity, Water",

author = "Nesmelov, {Yuri E.} and Anand Gopinath and Thomas, {David D.}",

note = "Funding Information: This work was supported by NIH Grants AR32961 (D.D.T.), AR48961 (Y.N.), and fellowship of University of Minnesota Supercomputing Institute (Y.N.).",

year = "2004",

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T2 - Sensitivity considerations

AU - Nesmelov, Yuri E.

AU - Gopinath, Anand

AU - Thomas, David D.

N1 - Funding Information: This work was supported by NIH Grants AR32961 (D.D.T.), AR48961 (Y.N.), and fellowship of University of Minnesota Supercomputing Institute (Y.N.).

PY - 2004/3

Y1 - 2004/3

N2 - The radial mode matching (RMM) method has been used to calculate accurately the microwave field distribution of the TE011 mode in a spherical EPR cavity containing a linear aqueous sample, in order to understand in detail the factors affecting sensitivity in EPR measurements at X band. Specific details of the experiment were included in the calculations, such as the cavity geometry, the presence of a quartz dewar, the size of the aqueous sample, and the sample's dielectric properties. From the field distribution, several key physical parameters were calculated, including cavity Q, filling factor, mean microwave magnetic field at the sample, and cavity efficiency parameter Λ. The dependence of EPR signal intensity on sample diameter for a cylindrical aqueous sample was calculated and measured experimentally for non-saturated and half-saturated samples. The optimal aqueous sample diameter was determined for both cases. The impact of sample temperature, conductivity, and cavity Q on sensitivity of EPR is discussed.

AB - The radial mode matching (RMM) method has been used to calculate accurately the microwave field distribution of the TE011 mode in a spherical EPR cavity containing a linear aqueous sample, in order to understand in detail the factors affecting sensitivity in EPR measurements at X band. Specific details of the experiment were included in the calculations, such as the cavity geometry, the presence of a quartz dewar, the size of the aqueous sample, and the sample's dielectric properties. From the field distribution, several key physical parameters were calculated, including cavity Q, filling factor, mean microwave magnetic field at the sample, and cavity efficiency parameter Λ. The dependence of EPR signal intensity on sample diameter for a cylindrical aqueous sample was calculated and measured experimentally for non-saturated and half-saturated samples. The optimal aqueous sample diameter was determined for both cases. The impact of sample temperature, conductivity, and cavity Q on sensitivity of EPR is discussed.

KW - Cavity

KW - EPR

KW - Field distribution

KW - Sensitivity

KW - Water

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EP - 146

JO - Journal of Magnetic Resonance

JF - Journal of Magnetic Resonance

IS - 1

ER -

Aqueous sample in an EPR cavity: Sensitivity considerations

Abstract

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