Novel HTS DC Squid Solutions for NMR Applications
We have developed a multilayer flux-transformer-based high-T C SQUID (flip-chip) magnetometer that improves signal-to-noise-ratios (SNR) in ultra-low field magnetic resonance (ulf-MR) recordings of protons in water. Direct ulf-MR-based benchmarking of the flip-chip versus a standard planar high-T C SQUID magnetometer resulted in improvement of the SNR by a factor of 2. This gain is attributable to the improved transformation coefficient (1.9 vs 5.3 nT/Φ0) that increased the signal available to the flip-chip sensor and to the lower noise at the measurement frequency (15 vs 25 fT/Hz1/2 at 4 kHz). The improved SNR can lead to better spectroscopic resolution, lower imaging times, and higher resolution in ulf-MR imaging systems based on high-T C SQUID technology. The experimental details of the sensors, calibration, and ulf-MR benchmarking are presented in this report.
KeywordsChemical Mechanical Polishing Squid Magnetometer Pickup Coil Input Coil Squid Sensor
We thank the European Union for support of the FP7 project “MEGMRI”, contract number 200859, the Swedish Research Council, Knut and Alice Wallenberg foundation, the European Union via Tillväxtverket and Regionala Utvecklingsfonden for MedTech West, and Kristina Stenborgs stiftelse for financial support. Authors from Russian Federation thank the Russian Ministry of Education and Science for financial support under grant 14.513.11.0009.
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