title: Spin Noise Detection of Nuclear Hyperpolarization at 1.2 K.
abstract: We report proton spin noise spectra of a hyperpolarized solid sample of commonly used "DNP (dynamic nuclear polarization) juice" containing TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxide) and irradiated by a microwave field at a temperature of 1.2 K in a magnetic field of 6.7 T. The line shapes of the spin noise power spectra are sensitive to the variation of the microwave irradiation frequency and change from dip to bump, when the electron Larmor frequency is crossed, which is shown to be in good accordance with theory by simulations. Small but significant deviations from these predictions are observed, which can be related to spin noise and radiation damping phenomena that have been reported in thermally polarized systems. The non-linear dependence of the spin noise integral on nuclear polarization provides a means to monitor hyperpolarization semi-quantitatively without any perturbation of the spin system by radio frequency irradiation.
authors.affiliation: Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040, Linz, Austria.
authors.forename: Maria Theresia
authors.initials: MT
authors.lastname: Pöschko
authors.affiliation: Institut de Sciences et Ingénerie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.
authors.forename: Basile
authors.initials: B
authors.lastname: Vuichoud
authors.affiliation: Institut de Sciences et Ingénerie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.
authors.forename: Jonas
authors.initials: J
authors.lastname: Milani
authors.affiliation: Institut de Sciences et Ingénerie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Bornet
authors.affiliation: Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040, Linz, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Bechmann
authors.affiliation: Institut de Sciences et Ingénerie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.|Département de Chimie, Ecole Normale Supérieure, PSL, 24 Rue Lhomond, 75231, Paris, Cedex 05, France.|Université Pierre-et-Marie Curie, 4 Place Jussieu, 75005, Paris (France.|UMR 7203, CNRS/UPMC/ENS, Ecole Normale Supérieure, Paris, France.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Bodenhausen
authors.affiliation: Institut de Sciences et Ingénerie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland. sami.jannin@epfl.ch.|Bruker BioSpin AG, Industriestrasse 26, 8117, Fällanden, Switzerland. sami.jannin@epfl.ch.
authors.forename: Sami
authors.initials: S
authors.lastname: Jannin
authors.affiliation: Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040, Linz, Austria. norbert.mueller@jku.at.|Faculty of Science, University of South Bohemia, Branišovská 1645/31A, 370 05, České Budějovice, Czech Republic. norbert.mueller@jku.at.
authors.forename: Norbert
authors.identifier: http://orcid.org/0000-0002-7621-3980
authors.initials: N
authors.lastname: Müller
keywords: dynamic nuclear polarization; non-linear effects; nuclear magnetic resonance; radiation damping; spin noise