Abstract
Following the success of cryogenic EPR signal preamplification at X-band, we present a Q-band EPR cryoprobe compatible with a standard EPR resonator. The probehead is equipped with a cryogenic ultra low-noise microwave amplifier and its protection circuit that are placed close to the sample in the same cryostat. Our cryoprobe maintains the same functionality and compatibility as the commercial instrument allowing high-power pulsed EPR experiments of typical samples. The performance of our setup is benchmarked using pulsed EPR and ENDOR experiments revealing a significant sensitivity improvement, which reduces the measurement time by a factor of about 40x at low temperature.