Progress Towards a Higher Sensitivity 13C-Optimized 1.5 mm HTS NMR Probe

IEEE Trans Appl Supercond. 2021 Aug;31(5):1500504. doi: 10.1109/tasc.2021.3061042. Epub 2021 Feb 22.


Nuclear magnetic resonance (NMR) probes using thin-film high temperature superconducting (HTS) resonators offer high sensitivity and are particularly suitable for small-sample applications. We are developing an improved 1.5 mm HTS NMR probe designed for operation at 14.1 T and optimized for 13C detection. The total sample volume is about 35 μL and the active sample volume is 20 μL. The probe employs HTS resonators for 13C and 1H transmission and detection and the 2H lock. We examine the interactions of multiple superconducting resonators and normal metal tuning loops on coil resonance frequency and probe sensitivity. We test a recently introduced 13C resonator design, engineered to significantly increase 13C detection sensitivity over previous all-HTS probes. At zero field, we observe a 13C quality factor of 6000 which is several times higher than previous resonators. In this work the coil design considerations and probe build-out procedure are discussed.

Keywords: Nuclear magnetic resonance; high-temperature superconductors; superconducting devices.