In order to observe low field $\sigma$ EPR spectra of free radicals a new probe head was designed to work at 1.53 mT. As a double resonance spectrometer, at 1.53 mT the probe head includes both NMR and EPR rf coils. To induce the $\sigma$ transitions EPR rf coil must produce an rf field parallel to the main static field. Various coil designs were examined for this aim and the best results was obtained with a solenoid NMR coil and saddle shaped single turn EPR coil design combination.
SALMAN, A. Oral; SÜNNETÇİOĞLU, M. Maral; SUNGUR, Rıza; and BİNGÖL, Gökçe (1998) "A New Probe Head Design for the Weak Field Double Resonance Spectrometer," Turkish Journal of Physics: Vol. 22: No. 8, Article 7. Available at: https://journals.tubitak.gov.tr/physics/vol22/iss8/7