UHF EPR spectrometer operating at frequencies between 400 MHz and 1 GHz

A spectrometer was designed and constructed to facilitate measurements of T 1 , T 2 , spin echo signal‐to‐noise, and resonator quality factor, Q , between about 400 and 1000 MHz. Pulse patterns are generated at 250 MHz and mixed with the output from a second source to perform excitation and detection. A cross‐loop resonator was constructed in which the same sample could be measured in the same resonator over the full range of frequencies. An air‐core, four‐coil, water‐cooled electromagnet with a large experimental volume was built.