X- and Q-band EPR with cryogenic amplifiers independent of sample temperature.
Cryoprobe
EPR
LNA
Noise
SNR
Sensitivity
Journal
Journal of magnetic resonance (San Diego, Calif. : 1997)
ISSN: 1096-0856
Titre abrégé: J Magn Reson
Pays: United States
ID NLM: 9707935
Informations de publication
Date de publication:
Jan 2023
Jan 2023
Historique:
received:
27
10
2022
revised:
03
12
2022
accepted:
04
12
2022
pubmed:
15
12
2022
medline:
15
12
2022
entrez:
14
12
2022
Statut:
ppublish
Résumé
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 [Šimėnas 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.
Identifiants
pubmed: 36516664
pii: S1090-7807(22)00214-2
doi: 10.1016/j.jmr.2022.107356
pii:
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
107356Informations de copyright
Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.
Déclaration de conflit d'intérêts
Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Mantas Simenas reports a relationship with Amplify My Probe Ltd. that includes: equity or stocks. Vidmantas Kalendra reports a relationship with Amplify My Probe Ltd. that includes: equity or stocks.]