Wenckebach, W. ThCapozzi, A.Patel, S.Ardenkjaer-Larsen, J. H.2021-06-052021-06-052021-06-052021-06-0110.1016/j.jmr.2021.106982https://infoscience.epfl.ch/handle/20.500.14299/178627WOS:000652024400003A previous study of the effect of Gadolinium doping on the dynamic polarization (DNP) of C-13 using trityls showed that the rate at which the polarization builds up is almost independent of the Gadolinium concentration, while the electron spin-lattice relaxation rate varies over an order of magnitude. In this paper we analyze the polarization build-up in detail and show that in this case DNP is due to the cross-effect (CE) and that the build-up rate can be quantitatively interpreted as the rate of the triple spin flips responsible for the CE. Thus this build-up rate presents a direct measurement of this triple spin flip rate. (C) 2021 Elsevier Inc. All rights reserved.Biochemical Research MethodsPhysics, Atomic, Molecular & ChemicalSpectroscopyBiochemistry & Molecular BiologyPhysicsdynamic nuclear polarizationhyperpolarizationcross effectthermal mixingtriple spin flip ratemagnetic-resonance saturationtrityl ox063zeemangd3+dnptext::journal::journal article::research article