The CW-EPR Capabilities of a Dual DNP/EPR Spectrometer Operating at 14 and 7 T

Orit Nir-Arad, David H. Shlomi, Amit Israelstam, Tomer Amit, Nurit Manukovsky, Alexander B. Fialkov, Ilia Kaminker

Research output: Contribution to journalArticlepeer-review


High-field electron paramagnetic resonance (EPR) measurements are indispensable for a better understanding of dynamic nuclear polarization (DNP), which relies on polarization transfer between electron and nuclear spins. DNP experiments are typically performed at high > 7 T magnetic fields and low ≤ 100 K temperatures, while EPR instrumentation capable of EPR measurements under these conditions is scarce. In this paper, we describe the CW EPR capabilities of a dual DNP/EPR spectrometer that is designed to carry out EPR experiments under “DNP conditions” at 14 and 7 T. In the first part, we present the design of this instrument, highlighting the choices made to allow for both DNP and EPR operations. The spectrometer uses a sweepable cryogen-free magnet with NMR-grade homogeneity, a closed-cycle cooling system, a quasi-optical induction mode bridge, and a superheterodyne receiver system. The probe design is optimized for low heat load and fast sample exchange under cryogenic conditions. The spectrometer can operate in frequency and field sweep modes, including wide field sweeps using the main coil of the magnet. In the second part, we present EPR spectra acquired over a wide range of samples and operating conditions, illustrating the CW EPR capabilities of the instrument.

Original languageEnglish
Article number107635
StatePublished - Mar 2024


  • Cryogen-free magnet
  • Cryogenic operation
  • Electron paramagnetic resonance
  • Frequency sweep
  • High-field electron paramagnetic resonance
  • Induction mode
  • Quasi optics
  • Superheterodyne detection

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Nuclear and High Energy Physics
  • Condensed Matter Physics


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