These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: A rectangular loop-gap resonator for EPR studies of aqueous samples.
    Author: Piasecki W, Froncisz W, Hubbell WL.
    Journal: J Magn Reson; 1998 Sep; 134(1):36-43. PubMed ID: 9740728.
    Abstract:
    A new rectangular geometry of the loop-gap resonator for the use with a flat cell has been developed. Maxwell's equations for the resonators with two, four, six, and eight gaps have been solved assuming the existence of only the magnetic z-component. The formulas obtained were numerically solved for the electric and magnetic field distributions over the cross-sections of the resonators. The presence of a nodal plane for the electric field in the center of the resonator allows the use of a flat cell instead of a capillary for EPR measurements. Using the field distributions obtained, the quality factor and EPR signal amplitude for various shapes and gap numbers for the resonators containing a flat cell filled with water were examined numerically. This allowed finding the geometry that yields the maximum EPR signal intensity. Several X-band resonators were built in order to verify the results obtained theoretically. The experiments confirmed the ability of a novel resonant structure to accommodate a flat cell filled with an aqueous sample. It has been found that the optimum aqueous sample volume for the X-band rectangular loop-gap resonator equals 16 mm3. For a saturable aqueous sample this gives a fourfold improvement in the S/N ratio over the circular 1 mm i.d. loop-gap resonator equipped with 0.6 mm i.d. capillary.
    [Abstract] [Full Text] [Related] [New Search]