| Title |
X- and Q-band EPR with cryogenic amplifiers independent of sample temperature / |
| Authors |
Kalendra, Vidmantas ; Turčak, Justinas ; Banys, Jūras ; Morton, John J. L ; Šimėnas, Mantas |
| DOI |
10.1016/j.jmr.2022.107356 |
| Full Text |
|
| Is Part of |
Journal of magnetic resonance.. San Diego : Elsevier. 2023, vol. 346, art. no. 107356, p. [1-8].. ISSN 1090-7807. eISSN 1096-0856 |
| Keywords [eng] |
EPR ; cryoprobe ; LNA ; sensitivity ; noise ; SNR |
| Abstract [eng] |
Inspired by the success of NMR cryoprobes, we recently reported a leap in X-band EPR sensitivity by equipping an ordinary EPR probehead with a cryogenic low-noise microwave amplifier placed closed to the sample in the same cryostat [Šime˙ nas et al. J. Magn. Reson. 322, 106876 (2021)]. Here, we explore, theoretically and experimentally, a more general approach, where the amplifier temperature is independent of the sample temperature. This approach brings a number of important advantages, enabling sensitivity improvement irrespective of sample temperature, as well as making it more practical to combine with ENDOR and Q-band resonators, where space in the sample cryostat is often limited. Our experimental realisation places the cryogenic preamplifier within an external closed-cycle cryostat, and we show CW and pulsed EPR and ENDOR sensitivity improvements at both X- and Q-bands with negligible dependence on sample temperature. The cryoprobe delivers signal-to-noise ratio enhancements that reduce the equivalent pulsed EPR measurement time by 16 at X-band and close to 5 at Q-band. Using the theoretical framework we discuss further improvements of this approach which could be used to achieve even greater sensitivity. |
| Published |
San Diego : Elsevier |
| Type |
Journal article |
| Language |
English |
| Publication date |
2023 |
| CC license |
|
