Q-band EPR cryoprobe

Vidmantas Kalendra; Justinas Turčak; Gediminas Usevičius; Hugo Karas; Miriam Hülsmann; Adelheid Godt; Gunnar Jeschke; Jūras Banys; John J L Morton; Mantas Šimėnas

doi:10.1016/j.jmr.2023.107573

Q-band EPR cryoprobe

J Magn Reson. 2023 Nov:356:107573. doi: 10.1016/j.jmr.2023.107573. Epub 2023 Oct 13.

Authors

Affiliations

¹ Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania; Amplify My Probe Ltd., London NW1 1NJ, UK.
² Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania.
³ Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich, Switzerland.
⁴ Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.
⁵ London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Electronic & Electrical Engineering, University College London, London WC1E 7JE, UK.
⁶ Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania. Electronic address: mantas.simenas@ff.vu.lt.

PMID: 37856964
DOI: 10.1016/j.jmr.2023.107573

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 sample access and tuning which is typical in Q-band EPR, as well as supports high-power pulsed experiments on typical samples. The performance of our setup is benchmarked against that of existing commercial and home-built Q-band spectrometers, using CW EPR and pulsed EPR/ENDOR experiments to reveal a significant sensitivity improvement which reduces the measurement time by a factor of about 40× at 6 K temperature at reduced power levels.

Keywords: Cryoprobe; EPR; LNA; Noise; Q-band; Sensitivity.