Table 3 Routine DNP procedure conducted before and during each DNP experiments.
From: Performance and reproducibility of 13C and 15N hyperpolarization using a cryogen-free DNP polarizer
Step | Parameter | Comments | Standard settings |
|---|---|---|---|
1 | Fluid path | Flush the sample path before inserting the sample | |
2 | 13C transmitter frequency | Compare to calibrated value. Coincides with the center of the spectrum | ± 10 kHz to calibrated value; adjust 13C and µW frequencies if deviation is larger |
3 | 13C resonance frequency | Compare to transmitter frequency | |
4 | Resonance of the coil | Adjust variable capacitors if necessary | Reflection less than 10% |
5 | µW frequency, power and mode | Calculate µW maximum frequency from 13C resonance frequency. Constant µW mode | |
6 | Buildup rate | Observe for abnormalities. Analysis mode should be set to integral | |
7 | Monitor SS signal | Check for good SNR |
