A chip-based C-band ODNP platform

Qing Yang; Jianyu Zhao; Frederik Dreyer; Daniel Krüger; Anh Chu; Michal Kern; Bernhard Blümich; Jens Anders

doi:10.1016/j.jmr.2023.107603

A chip-based C-band ODNP platform

J Magn Reson. 2024 Jan:358:107603. doi: 10.1016/j.jmr.2023.107603. Epub 2023 Dec 23.

Authors

Qing Yang¹, Jianyu Zhao¹, Frederik Dreyer¹, Daniel Krüger², Anh Chu¹, Michal Kern¹, Bernhard Blümich³, Jens Anders⁴

Affiliations

¹ Institute of Smart Sensors, University of Stuttgart, Pfafenwaldring 47, Stuttgart, 70569, Germany.
² Institute of Smart Sensors, University of Stuttgart, Pfafenwaldring 47, Stuttgart, 70569, Germany; John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, 02138, United States.
³ Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, Aachen, 52074, Germany.
⁴ Institute of Smart Sensors, University of Stuttgart, Pfafenwaldring 47, Stuttgart, 70569, Germany; Center for Integrated Quantum Science and Technology (IQ(ST)), Stuttgart, Germany; Institute for Microelectronics Stuttgart (IMS CHIPS), Stuttgart, Germany. Electronic address: jens.anders@ite.uni-stuttgart.de.

PMID: 38142565
DOI: 10.1016/j.jmr.2023.107603

Abstract

In this paper, we present a chip-based C-band ODNP platform centered around an NMR-on-a-chip transceiver and a printed microwave (MW) Alderman-Grant (AG) coil with a broadband tunable frequency range of 528MHz. The printable ODNP probe is optimized for a high input-power-to-magnetic-field conversion-efficiency, achieving a measured ODNP enhancement factor of -151 at microwave power levels of 33.3dBm corresponding to 2.1W. NMR measurements with and without microwave irradiation verify the functionality and the state-of-the-art performance of the proposed ODNP platform. The wide tuning range of the system allows for indirect measurements of the EPR signal of the DNP agent by sweeping the microwave excitation frequency and recording the resulting NMR signal. This feature can, e.g., be used to detect line broadening of the DNP agent. Moreover, we demonstrate experimentally that the wide tuning range of the new ODNP platform can be used to perform multi-tone microwave excitation for further signal enhancement: Using a 10mM TEMPOL solution, we improved the enhancement by a factor of two.

Keywords: Alderman-grant coil; C-band DNP; Dynamic nuclear polarization; Multi-tone excitation; NMR-on-a-chip transceiver; Printed coils.