title: An Alderman-Grant resonator for S-Band Dynamic Nuclear Polarization.
abstract: An Alderman-Grant resonator with resonance at 2GHz (S-Band) was simulated, developed and constructed for Dynamic Nuclear Polarization (DNP) experiments at 73mT. The resonator fits into magnet bores with a minimum diameter of 20mm and is compatible with standard 3mm NMR tubes. The compact resonator design achieves good separation of electric and magnetic fields and therefore can be used with comparatively large sample volumes with only small sample heating effects comparable to those obtained with optimized X- and W-Band DNP setups. The saturation efficiency and sample heating effects were investigated for Overhauser DNP experiments of aqueous solutions of TEMPOL radical, showing relative saturation better than 0.9 and sample heating not exceeding a few Kelvin even at high microwave power and long irradiation time. An application is demonstrated, combining the DNP setup with a commercial fast field cycling NMR relaxometer. Using this resonator design at low microwave frequencies can provide DNP polarization for a class of low-field and time-domain NMR experiments and therefore may enable new applications that benefit from increased sensitivity.
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany. Electronic address: neudert@mpip-mainz.mpg.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Neudert
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany. Electronic address: raich@mpip-mainz.mpg.de.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Raich
authors.affiliation: Institute of Physics, Ilmenau University of Technology, D-98693 Ilmenau, Germany. Electronic address: carlos.mattea@tu-ilmenau.de.
authors.forename: Carlos
authors.initials: C
authors.lastname: Mattea
authors.affiliation: Institute of Physics, Ilmenau University of Technology, D-98693 Ilmenau, Germany. Electronic address: siegfried.stapf@tu-ilmenau.de.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Stapf
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany. Electronic address: muenne@mpip-mainz.mpg.de.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Münnemann
keywords: Alderman–Grant resonator; Dynamic Nuclear Polarization; Field cycling NMR; Hyperpolarization; Low field NMR; Overhauser DNP; Relaxometry; Time domain NMR