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

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
¹³
C detection. The total sample volume is about 35 μL and the active sample volume is 20 μL. The probe employs HTS resonators for
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C and
¹
H transmission and detection and the
²
H 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
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C resonator design, engineered to significantly increase
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C detection sensitivity over previous all-HTS probes. At zero field, we observe a
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C 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.